AI Money Labs

Income models

Micro SaaS

「Build once, charge many times」

Selling costs you no hours. Building costs you all of them, and you do not get them back if nobody buys. The risk points the other way from the six models above.

Level 4

Sell small software that solves a narrow problem, on subscription. The longest route and the highest failure rate — and the only band where revenue arrives in a month you did not work.

Difficulty
5/5
To first revenue
Building takes months. Time to a first paying subscription is not something we estimate — this is where most people stop.
Startup cost
₩100,000~2,000,000
Coding
a lot
Sales
some
Automation
5/5

We have zero cases with a verified earnings figure, so we do not invent a revenue range. What follows instead is arithmetic on published prices and official fee rates.

Where the money goes

One sale, start to finish — Monthly

What the customer pays$15

This is also the figure you report as revenue — not the amount that reaches your account.

The payment provider takes its cut
  • Transaction fee (5%)−$0.75
  • Fixed fee per transaction (건당 $0.50)−$0.50
What lands in your account$13.7592% of list

The provider sells as merchant of record, so it handles sales tax in each country. That is why no VAT line follows — the tax did not vanish, someone else remits it.

The ceiling you cannot pass in a month

Published delivery days divided into the working month. Not what you can earn — the line you cannot cross alone.

What these numbers are, and are not

  • Nobody earned this. Not one listed case has a verified revenue figure.
  • List prices and delivery days come off the seller's page; fee rates come from the platform's own documentation.
  • “Max/mo” is division — 20 working days divided by the published delivery time. It does not mean orders arrive that steadily. In practice they do not.
  • Operating profit here is before tool costs, your own labour and income tax. Rework and refunds are not in it either.

Who you sell to

  • A specific profession
  • Small operators
  • A narrow group with one shared problem

How the money comes in

  • Monthly subscription
  • Usage-based billing

Steps

  1. Pick one friction in work you already know
  2. Build the smallest version and put it in front of ten people
  3. Ask whether they would pay — using and paying are different
  4. For expensive generation, consider having users bring their own API key

Tools used

Claude API · OpenAI API · Cursor · GitHub Copilot

Linked tools are ones whose pricing we checked and listed.

Risks

  • The stretch before first revenue is long, and you need to live on something during it
  • Selling is harder than building — engineers fall into this one hardest
  • If a general model absorbs the feature, the product is replaced wholesale
  • Products with a dozen subscriptions are commonly listed for sale — that is the reality of this band

Verified cases using this model

Compare with

Do this today

  1. Write down three frictions that recur weekly in your work
  2. Pick the one others would also hit
  3. Search for products already solving it — if any exist, write down their prices

Run your own break-even →