The smallest thing you can charge for
A minimum paid version, cut down until it’s almost embarrassing, proves willingness to pay faster than any feature you could add first.
The target-arithmetic work and the price-as-positioning argument both assumed a finished product, a listed price, and a stranger deciding whether to buy it. Nothing about either one required the product to actually be finished. This lesson is about the gap between those two things — between a project that is still half-built and the first dollar it could earn this month, not eventually.
You do not need the finished product to charge
Rob Fitzpatrick’s The Mom Test spends its earlier chapters teaching you not to trust what people say in a conversation. Chapter 5 is where it gets specific about what to trust instead: commitment, defined as “showing they’re serious by giving up something they value such as time, reputation, or money” (Fitzpatrick, The Mom Test, ch. 5, 2013 self-published edition — the wording quoted here and below is that edition’s; the later revised and expanded edition’s text has not been checked against it). Three currencies, not one — and the book is explicit that cash is not required: “Commitment can be cash, but doesn’t have to be.” A meeting on the calendar, an introduction to a decision-maker, a name attached to a public testimonial — all of those count.
Money is still worth singling out, and the book gives you the material to say why without overstating it. A next meeting can be rescheduled without cost. A testimonial can be given generously and forgotten by the person who gave it. A card that gets charged is the one currency that leaves no room to have half-meant it — which is why this lesson leans on it, not because The Mom Test ranks the three currencies against each other. It doesn’t; it just refuses to let “that sounds great” count as any of them.
The book is also specific that this does not wait for a finished product. Its example is a fan who pre-orders against “a duct-tape prototype” because the problem is real enough that they don’t need the polish first. A deposit or a pre-order in hand proves the person was telling the truth in a way a stated intention cannot — not because intentions are dishonest, but because they are free to state and easy to revise.
What “smallest” means when the product is half-built
A half-built recipe app for kids does not need to become a finished recipe app for kids before anyone can pay for it. It needs a slice narrow enough to actually finish this month, and finished in the sense that matters: complete on its own terms, not a preview of something bigger that isn’t built yet.
Jason Cohen draws that line precisely in his case against the MVP: the goal is not minimum, it is a narrow scope that is “complete according to that scope” (Cohen, “Your customers hate MVPs”, 2017 — the page also promotes his book and a paid course, worth knowing since the essay is otherwise unsourced opinion from a two-time founder). One meal plan, fully working, with no half-finished second feature visible next to it, is smaller than the whole app and it is not unfinished. A login screen that leads to three broken tabs is neither small nor finished — it is just incomplete, and incomplete is not a size, it’s a state nobody should be asked to pay to sit inside.
37signals makes the same cut from the other direction, in Getting Real’s advice for when a project is behind: “Never throw more time or money at a problem, just scale back the scope” (37signals, Getting Real, “Fix Time and Budget, Flex Scope”). Time and budget are fixed for a solo builder by definition — there are only so many evenings. Scope is the only variable left to move, and it is the same variable that turns a half-built project into something with an edge sharp enough to charge for this month.
The difference between a discount and a smaller scope
Neither book draws this next line explicitly — it doesn’t appear in The Mom Test or in Getting Real. This is the course’s own reasoning, offered because the two moves look similar on a pricing page and behave nothing alike as a test.
Cutting the price holds the promise fixed and moves the number: the same recipe app, all of it, for less. Cutting the scope holds the number roughly fixed and moves the promise: one meal plan generator, not the whole app, at close to what the whole thing would eventually cost. Both feel like “starting small.” Only one of them tells you anything.
A discount tests price sensitivity, and price sensitivity is nearly universal — offer almost anyone almost anything for less and a meaningful fraction will say yes. That is not evidence the product solves a problem; it is evidence that cheap is appealing, which you already knew. A smaller scope, priced honestly for what it actually does, tests something else: whether the narrower, real thing you shipped is worth a stranger’s money on its own terms, with nothing bigger promised to prop it up.
What a first payment actually proves — and what it doesn’t
One payment proves that a specific person, for a specific narrow version of the thing, judged it worth a currency that costs them something to give up. That is real, and it is more than a conversation can produce on its own — which is the whole argument of The Mom Test’s earlier chapters, applied here to the sharpest currency it names.
It does not prove the price is right for anyone but that buyer. It does not prove a second person exists, let alone the dozens the target-arithmetic math needs. It does not prove the maintenance load this scope generates is affordable at the price charged, which is a separate measurement this course has already asked you to make elsewhere. And per the book’s own close of the chapter that makes the case for charging early: the point was never the money itself. Chapter 5 ends by naming learning as the real goal of an early sale, with revenue arriving as a side-effect of getting that learning right — not the other way around. A lesson that told you to charge because the money is the point would be misreading its own source.
So the payment is a floor, not a verdict. What it buys you is a real person who will now answer the harder questions honestly — what nearly stopped them, what they’d trade the feature away for, whether they’d pay it again — the same discipline the Demand gate asked for earlier, now aimed at someone who has already proven they meant it.
Retrieval check
Nobody has paid for your half-built thing. What is the smallest version you could charge for this month?
Check your answer
The honest answer separates two moves that are easy to blur on a pricing page. A smaller product is a test: a narrower scope, complete on its own terms, sold near what it actually costs to deliver. A cheaper product is a discount: the same thing you already had, for less, which mostly tells you that a lower number is appealing — something almost everyone already knew.
Only the first one tells you anything, because only the first one changes what the buyer is being asked to value. If your answer to this prompt moved a number and left the promise untouched, go back and cut the promise instead — that is the version worth charging for.
Charge the narrow slice this month
Hands on
Name the smallest paid version
Done when: A new Smallest paid version field exists in PORTFOLIO.md for one project — naming a scope cut down to its smallest complete slice, a price, and who that slice is for.
- Pick one half-built or built-live project from your shelf — the one you are least tempted to keep polishing before you test anything.
- Write down the whole promise the finished product would eventually make. Then cross out everything that is not load-bearing for one named use case. What is left is the candidate slice — check it against Cohen’s test: is it complete for that narrow scope, or just smaller and still broken?
- Price the slice on its own terms, not as a fraction of the eventual whole. If the number you land on is lower only because you flinched, that is a discount wearing a scope’s clothes — raise it back to what the slice is actually worth to the one buyer it serves.
- Add a new field to that project’s entry in
learning/monetizing/PORTFOLIO.md: Smallest paid version. One line for the scope, one for the price, one sentence naming who it’s for. The field does not exist yet anywhere in the ledger — you are adding it, not filling in a blank that was waiting for you. - Bring it into the chat. I’ll push on whether what you cut is actually a scope or just a smaller price tag on the same promise — that is the mistake this lesson exists to catch.
What this does not cover
A smallest paid version is a decision about scope and price. It says nothing about the mechanics underneath it: what has to be wired up before a stranger can actually hand you money, and the handful of decisions — currency, tax, refunds — that get expensive to change once real customers exist. That’s next.
Read this next — primary source
Commitment and AdvancementRob Fitzpatrick, The Mom Test (2013 self-published edition), ch. 5 — paperback, Kindle, audiobook and PDF from momtestbook.com. Fitzpatrick sells the book; there is no free full text.
This is the chapter where the book stops talking about conversations and starts talking about proof. It names the currencies a person can spend to show they mean it — time, reputation, cash — and it is specific about deposits and pre-orders as the sharpest version of that proof. It is also the chapter that keeps itself honest about what all of this is for: it closes by naming revenue a side-effect of learning, not the goal, which is worth having in view before this lesson borrows its argument.
Stuck, curious, or think this lesson is wrong? Ask your teaching agent. The lessons are the scaffold; the conversation is where the learning gets unstuck.