How to Test a Business Idea Before You Spend Money (St. Louis)
Revised July 27, 2026
How do I know if my business idea will work?
⚠️ The “90% of businesses fail” line has no federal basis — BLS found 34.7% of establishments born in 2013 were still operating ten years later. Missouri does NOT register sole proprietorships (the Secretary of State “does not receive or accept filings” creating them); a fictitious name is $7 and only needed for a trade name. Four separate triggers, four different answers: using a trade name → $7 fictitious name registration; selling goods → sales tax license BEFORE your first sale; hiring anyone → employer withholding registration; wherever you physically work → a local business license. A state-level exemption is NOT a local exemption. The sales tax license is required before your first sale — penalty $500 first day + $100/day up to $10,000, and it’s a misdemeanor. 🏠 The City of St. Louis requires a business license even for home businesses, and prohibits restaurants, repair shops, kenneling, auto work and more as home occupations. Cottage food (baked goods, jam/jelly, dried herbs ONLY) needs no state permit — but city zoning still treats home food processing as a conditional use. 🤖 Stanford found 69–88% hallucination rates on specific legal questions — verify anything about money or licensing with the actual agency. Free help: SBDC 314-241-1005 and SCORE.
Keep reading ↓You have probably heard that ninety percent of new businesses fail.
That number has no basis in federal data. The Bureau of Labor Statistics tracks this directly, and of the private-sector establishments that opened in March 2013, 34.7% were still operating ten years later.
About a third still going after a decade. Not ten percent. And “closed” isn’t the same as “failed” — businesses get sold, merged, and retired from.
That’s a better starting point than the myth, and it sets up the real question: how do you find out whether your idea has customers, before you spend money finding out the expensive way?
How do I know if my business idea will work?
Three checks, all free, in this order. Test demand using Google Trends to compare your idea against alternatives — but know it shows relative interest only and filters low-volume searches to zero, so a niche local idea can look dead when it isn’t. Check what’s legally required where you live — Missouri doesn’t register sole proprietorships at all, but the City of St. Louis does require a business license, and some home occupations are prohibited outright. Then talk to ten people who would actually pay you. That last one is the only step that tests willingness to pay rather than curiosity.
What Google Trends will and won’t tell you
Google Trends is free and genuinely useful, and it is also the single most misread tool in this whole process. Google publishes its limits, so here they are.
The numbers are relative, never absolute. Each point is divided by total searches for that geography and time range, then scaled 0 to 100. A 100 does not mean “a lot of people.” It means “the busiest point on this particular chart.” Two ideas can both peak at 100 with wildly different real volume.
Low-volume searches are filtered out and display as zero. This is the one that will mislead you. If you are checking a specific service in a specific St. Louis suburb, a flat zero line is entirely consistent with real, paying demand — there just aren’t enough searches to clear Google’s threshold. Do not conclude nobody wants it.
Also worth knowing: Trends uses a sample rather than every search, removes duplicate searches from the same person, filters special characters including apostrophes, excludes searches made through Google’s own AI features, and adds statistical noise for privacy that is “most visible in low-volume queries.” Google itself says the data is “not a perfect mirror of search activity.”
Use it the way it’s built. Comparison is what it does well. Instead of asking “is there demand for X,” put X and Y side by side and see which is rising. That question the tool can actually answer.
Google’s Keyword Planner is the other free option. It requires a Google Ads account, though not ad spend. In practice, accounts without an active campaign tend to see broad ranges rather than precise numbers, and it groups a keyword with its close variants — so treat what you get as a family of searches, roughly sized.
What Missouri actually requires — less than you think
Here is something that saves people money and almost nobody says clearly. From the Missouri Secretary of State’s own website:
“Sole proprietorships and general partnerships can be formed or created without the involvement of the Secretary of State. In fact, the Secretary of State does not receive or accept filings related to the creation of these business types.”
You do not register a sole proprietorship in Missouri. If you mow lawns under your own legal name, you already are one. There is nothing to file and nothing to pay, and any service charging you to “register your sole proprietorship” with the state is selling you a filing that doesn’t exist.
You need a fictitious name registration only if you trade under a name that isn’t yours — “Gateway Lawn Care” instead of “Jane Smith.” That costs $7.00, lasts five years, and is filed with the Secretary of State.
One caveat the state states outright and most people assume the opposite of: “Filing a fictitious name registration does not afford or secure any exclusive rights to the name.” Somebody else can register the same one. It is a disclosure, not a trademark.
The one that carries real penalties
If you are going to sell products — at a craft fair, a farmers market, online — you need a Missouri sales tax license before your first sale. Not after the first good month.
The Department of Revenue is specific about what happens otherwise: $500 for the first day of operation and $100 for every day after, up to $10,000. And operating without one “is a misdemeanor and can result in criminal prosecution.”
The license itself is free to obtain, filed on Form 2643, and takes roughly ten business days. Bonds haven’t been required since 2018 for most new applicants.
Ten business days is exactly the kind of thing that ruins a plan to sell at a fair three weekends from now. Start it early.
There is a second trigger people miss entirely, and it has nothing to do with selling anything. The moment you hire someone — even one part-time helper — you take on employer obligations, including registering for Missouri employer withholding tax. The Department of Revenue handles that on the same registration application as the sales tax license, so if you already know you’ll have help, do both at once. Ask the Department directly which tax types your situation requires; that call is free and it is the correct place to get the answer.
So there are really four separate questions, and they have four different answers:
Are you using your own legal name? If yes, no state formation filing at all. If no, file the $7 fictitious name.
Are you selling goods? If yes, sales tax license before your first sale.
Are you hiring anyone? If yes, employer withholding registration.
Where are you physically working? Your city or county almost certainly wants a local business license.
That last one is where people get burned, so be clear on the logic: a state-level exemption is not a local exemption. Missouri not requiring you to register a sole proprietorship says nothing about whether St. Louis, Kirkwood or your county requires a license. Those are separate governments asking separate questions, and you have to answer both.
Working from home: the part that surprises people
If you are in the City of St. Louis, the city requires a business license for “any person who engages in any business, occupation, pursuit, profession, calling, a vocation, or trade” inside city limits. That includes working from your kitchen table.
There is a separate Home Occupancy application, and a home occupation waiver carrying a $50 fee. You must be a full-time resident of the property, and if you don’t own it, you need a notarized letter of authorization from whoever does. Fee amounts differ across the city’s own pages, so call the License Collector at 314-622-4800 and get your number from a person.
Now the part worth reading before you commit to an idea. The city lists uses that are prohibited as home occupations outright: restaurants, repair shops, animal boarding and kenneling, doctor and dentist offices, mortuaries, dancing schools, private clubs, tourist homes, and automobile repair, painting, sales, leasing, detailing or washing.
And uses requiring a conditional use permit rather than a straight approval: home daycares, recording and film studios, contractor home offices — and, notably, “home cooking, preserving or processing of food for resale.”
Read that list before you build a plan around detailing cars in your driveway or boarding dogs in your spare room.
If you are in unincorporated St. Louis County, different rules apply. And if you are in Kirkwood, Florissant, Ferguson, University City or any of the dozens of other municipalities here, your own city governs — which is the whole reason this can’t be answered generically. Call your city hall.
Selling food from home, and the conflict nobody flags
Food is one of the most common side hustles, so this deserves precision.
Missouri’s cottage food law lets you sell certain homemade foods with no permit, no license and no inspection. The 2022 update also removed the old $50,000 annual sales cap.
But the qualifying list is narrow. It covers baked goods, canned jam or jelly, and dried herbs or herb mixes. That’s the whole list. Not sauces, not prepared meals, not anything requiring refrigeration.
You must sell directly to consumers — no wholesale to shops or restaurants — and internet sales are permitted only when both you and the buyer are in Missouri. Your label has to carry your name and address plus a statement that the food is not inspected by any health department.
Here is the conflict, and it is exactly the kind of thing a chatbot will get wrong. State law says you need no permit. City of St. Louis zoning lists home food processing for resale as requiring a conditional use permit.
Both are true. The state preempted health regulation of cottage food. It did not preempt zoning. If you are baking for sale in the city, you need to satisfy the second rule even though the first one exempted you.
The people selling you AI shortcuts
If you are searching for ways to make money with AI, you are in the exact audience a set of federal defendants was targeting.
In September 2024 the Federal Trade Commission launched an enforcement sweep against deceptive AI claims and schemes. Among the documented cases: a company selling “AI-powered” online storefronts, charging customers tens of thousands of dollars, with alleged consumer harm exceeding $25 million. Another, selling AI-driven e-commerce automation, ended in a judgment over $15.7 million and a lifetime ban from selling business opportunities. A third settled in March 2026 with an $18 million judgment and a business-opportunity ban.
These were not fringe operators. They were the ones running the ads.
There is a specific federal rule that protects you here, and knowing it is worth more than any amount of skepticism. Under the FTC’s Business Opportunity Rule, anyone selling you a business opportunity must give you a written disclosure document covering: who they are, whether they make earnings claims, any legal actions against them in the past ten years involving fraud or misrepresentation, their cancellation and refund policy, and a list of prior purchasers — at least ten, with names, states and phone numbers. Plus a receipt for you to sign.
You are supposed to receive that before you pay anything.
So the test is simple: ask for the disclosure document and the reference list. A legitimate seller hands it over. Everyone else changes the subject — and that is your answer, for free, in about a minute.
The FTC’s other documented advice is worth repeating plainly: no honest employer asks you to pay to get a job, or sends you a check and asks you to send part of it back. Search any company name alongside the word “scam.” And talk it over with someone you trust — which mostly works by buying you time to think.
Where AI will confidently mislead you
AI is genuinely useful for the early work — organizing your thinking, drafting questions to ask customers, summarizing what competitors publish. It is unreliable at the exact thing you are most tempted to use it for: looking up a rule.
Stanford researchers tested this and published it in a peer-reviewed journal. Running more than 200,000 queries across three major language models, they found hallucination rates ranging from 69% to 88% on specific legal questions. The models invent citations, statutes and rules, and state them with complete confidence.
Worse for someone in your position, they documented what they call contra-factual bias — the models fail to challenge a false premise in your question. Ask “what permit do I need to run a restaurant out of my house in St. Louis” and you will get a confident answer, when the correct response is that the city prohibits restaurants as a home occupation entirely.
The researchers noted the risk runs highest for people without access to traditional legal resources. That is most people starting something on their own.
There are two more limits worth naming. Training cutoffs: Missouri removed the cottage food sales cap in 2022 and dropped the sales tax bond requirement in 2018 — a model that absorbed older material will hand you the old rule. And no model has local data: it does not know your ZIP code’s actual buyer count, and it has not read your municipality’s prohibited-use list.
We can prove that last point from writing this article. A well-ranking page told us no city permit or fee is required to run a home business in St. Louis. The city’s own website says a business license is required for anyone engaging in any business in the city. The confident answer was wrong, and it was wrong in the direction that would have cost the reader money.
Use AI to figure out what questions to ask. Then verify every answer that involves money, licensing or law against the actual agency.
Free help that exists specifically for this
Two organizations here will work with you before you have a business at all, at no cost. They are the most underused resource in this entire article.
The Missouri Small Business Development Center provides no-cost, confidential one-on-one advising, and its stated services explicitly include feasibility studies and identifying market opportunities — which is precisely what this article is about. The St. Louis regional office is at 314-241-1005.
SCORE St. Louis offers free, confidential mentoring from volunteers across a wide range of industries, in person or by email, plus free templates and workshops. It covers the city and county along with St. Charles, Jefferson, Franklin and into the Metro East, and it was named its district’s chapter of the year in early 2025.
A free hour with someone who has done this before will do more for your idea than any subscription, and considerably more than any course sold to you in an ad.
What this actually costs to find out
Add it up, for a home-based business in the City of St. Louis, before you buy a single piece of equipment:
Sole proprietorship registration: $0, because Missouri doesn’t do it.
Fictitious name, only if you use a trade name: $7.
Missouri sales tax license, if you sell goods: $0 to obtain.
Home occupation waiver: $50.
City business license: call 314-622-4800 for your figure.
SBDC and SCORE advising: free.
Under a hundred dollars, plus a few phone calls, to find out whether the thing is legal where you live and whether anyone will pay for it.
That is the whole argument. The expensive way to test a business idea is to build it first. The cheap way is a week of phone calls and honest conversations — and if the idea survives that, you will know considerably more than the third of businesses that are still standing a decade later knew when they started.
Frequently asked questions
Do 90% of new businesses fail?
No, and that figure has no federal basis. Bureau of Labor Statistics data shows 34.7% of private-sector establishments that opened in March 2013 were still operating ten years later — about a third. BLS also measures survival rather than failure, and closing is not the same as failing; businesses are sold, merged and retired from.
Do I need to register a sole proprietorship in Missouri?
Not with the Secretary of State — it states plainly that sole proprietorships are formed without its involvement and that it does not accept filings creating them. But four conditions change that: using a trade name means a $7 fictitious name registration; selling goods means a sales tax license; hiring anyone means employer withholding registration; and your city or county likely requires a local business license regardless.
Do I need to register with Missouri if I hire an employee?
Yes. Hiring even one part-time person creates employer obligations including Missouri employer withholding tax registration, handled through the Department of Revenue on the same registration application as a sales tax license. If you know you will have help, register for both at once and confirm which tax types apply by calling the Department.
Do I need a business license to work from home in St. Louis?
In the City of St. Louis, yes — the city requires a business license for anyone engaging in any business, occupation or trade within city limits, including from home. There is also a separate home occupancy application and a $50 home occupation waiver. Fee figures differ across city pages, so call the License Collector at 314-622-4800.
What home businesses are not allowed in St. Louis?
The city prohibits several as home occupations outright, including restaurants, repair shops, animal boarding and kenneling, doctor and dentist offices, mortuaries, dancing schools, tourist homes, and automobile repair, painting, sales, leasing, detailing or washing. Home daycares, recording studios, contractor offices and home food processing for resale require a conditional use permit.
Can I sell homemade food in Missouri without a license?
For a narrow list, yes. Missouri’s cottage food law covers baked goods, canned jam or jelly, and dried herbs or herb mixes — sold directly to consumers, with online sales only within Missouri, and labeled as not inspected. No permit or inspection is required by the state. But City of St. Louis zoning separately treats home food processing for resale as a conditional use, so check both.
Is Google Trends accurate for checking demand?
It is accurate for comparison and misleading for absolute volume. Google scales results 0 to 100 relative to the chart itself, filters out searches made by very few people so they display as zero, uses a sample rather than all searches, excludes searches made through its own AI features, and adds statistical noise. A niche local idea can show a flat zero and still have real demand.
How do I know if an online business opportunity is a scam?
Ask for the disclosure document. The FTC’s Business Opportunity Rule requires sellers to provide one before you pay, covering their identity, any earnings claims, legal actions against them in the past ten years, refund policy, and a list of at least ten prior purchasers with phone numbers. A legitimate seller provides it. Also: no honest employer asks you to pay to get a job.
Can AI tell me what licenses I need?
Not reliably. Stanford researchers found hallucination rates of 69% to 88% on specific legal questions across major AI models, plus a documented tendency not to challenge false premises in your question. Use AI to work out what to ask, then verify anything involving money, licensing or law with the actual agency — the Secretary of State, Department of Revenue, or your city hall.
If the idea survives all of that, the next problem is being findable. We run a St. Louis directory, so that’s our interest and we’ll say it plainly — a listing puts your name, service and area somewhere people and AI assistants actually look, which matters more when you have no reputation yet. Listing a new business takes a few minutes. Do the free government advising first — it’s worth more at this stage than anything we sell.
Also useful: how local businesses are actually using AI, and legitimate work-from-home jobs in St. Louis if a paycheck beats a business right now.
Written by a dedicated team of St. Louis locals who live, work, and play right here in the St. Louis metro. Founder Lane Forman and team are committed to building the region’s most trusted directory by verifying listings and connecting local businesses with loyal customers across Missouri and Illinois.