7. Money

People use the thing and nobody pays. You cannot say whether any price at all would cover the bills, because you have never counted what a single action costs you to serve.

If the product calls an AI on the user’s behalf, every action already has a cost, and the provider sends it back in the response. Put it on the event row right then or lose it: an hour later there is nowhere to look it up.

So the arithmetic goes first. What one user costs is three numbers: the cost of one action, the cost of a month with nobody in it, and how many payers close that month. In whole people, not percentages.

The same page shows how to measure that cost instead of estimating it. I lost months to this. I thought the column was there and empty; it had never existed, so every figure I quoted that spring was reconstructed from a rates table.

You pick the model before the price. Per action or per month is about the difference. Somebody who comes back on their own buys a subscription; somebody with a one-off job buys a pack. Each drags its own work behind it.

Then comes the harder half, where two pages disagree. The cost arithmetic suggests shaving the bills. Getting the first person to pay says the bills were never the problem. Pick a number, put the wall where it stops somebody, ask one person for money by hand.

A product nobody pays for and a product nobody has been asked to pay for look the same from here. Telling them apart is cheaper than another round of cost cutting. I did the cost cutting first.