--- title: "Unit Economics: Does Each Sale Make Money?" description: "A business can grow fast and lose more with every customer it wins. The test is what one more sale costs to win and to serve, against what it brings in." canonical: https://lightmysky.com/learn/life-skills/unit-economics-does-each-sale-make-money-mt_NUoV6LB-o4 source: https://lightmysky.com/learn/life-skills/unit-economics-does-each-sale-make-money-mt_NUoV6LB-o4.md retrieved: 2026-09-12 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Unit Economics: Does Each Sale Make Money? A business can grow fast and lose more with every customer it wins. The test is what one more sale costs to win and to serve, against what it brings in. Subject: Life Skills · Area: Entrepreneurship · Ages 16 to 18 Page: https://lightmysky.com/learn/life-skills/unit-economics-does-each-sale-make-money-mt_NUoV6LB-o4 ## Ready when they can - Work out the contribution from one sale after the costs that vary with it - Explain why acquisition cost has to be counted per customer, not per month - Say what growing faster does to a business whose unit economics are negative ## Lesson: Check each sale earns its keep A business can grow fast and lose more with every customer it wins. Every cost behaves one way when sales move: variable costs climb with each unit, while fixed costs sit still. Materials and delivery grow per sale, while rent and salaries wait untouched. Unit economics starts by sorting costs this way, because only the costs that move with the sale count against one sale. **Example.** Call the price P and the per-sale costs V, such as materials and delivery. The contribution from one sale is P minus V. If that number is negative, every sale loses money, and faster growth just burns cash faster. If it is positive, each sale helps cover the fixed base of rent and salaries. Two calculations then tell the truth. First, count acquisition cost per customer, not per month, since it is spent once to win the buyer but earned back over many orders. Second, find the break-even point: divide fixed costs by contribution per unit. Sell fewer and each month loses; sell more and profit starts. If the needed volume looks unreachable, the idea needs cheaper costs or a higher price. **Tip.** Price is not just cost plus a bit. It positions the product, rations demand, and sets the per-sale contribution. Skim high to signal quality, go low to grab share, or bundle to lift the average order. Test prices against real buyers, since guesses about value are usually wrong. Run what-if questions before spending real cash: a business whose lines never cross should not scale. **Recap.** Sort costs, check one sale, then decide whether growth helps or hurts. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Scaling Up](https://lightmysky.com/learn/life-skills/scaling-up-mt_7SsduPB2tP) - [Costs & Revenue](https://lightmysky.com/learn/life-skills/costs-and-revenue-mt_9gpUHWVKMR) ## Opens up - [The Smallest Version Worth Testing](https://lightmysky.com/learn/life-skills/the-smallest-version-worth-testing-mt_q7e_4e7BoN) - [Knowing When to Stop](https://lightmysky.com/learn/life-skills/knowing-when-to-stop-mt_Xh61d76aET)