# Unit Economics Vocabulary: COGS, Gross Margin, $/User, Contribution Margin — 9 Financial Concepts Every AI Engineer Must Know

> Source: https://sukruyusufkaya.com/en/learn/token-ekonomisi/birim-ekonomisi-sozlugu-cogs-gross-margin
> Updated: 2026-05-14T14:44:10.162Z
> Category: Token Ekonomisi & LLM Cost Optimization
> Module: Module 0: Why Cost, Why Now?
**TLDR:** 9 financial concepts you need to calculate an AI product's real cost: COGS, Gross Margin, $/Request, $/User, $/MAU, Contribution Margin, CAC, LTV, Payback Period. Each with concrete LLM examples.