The terms every marketplace seller eventually has to learn.

Advertising return after platform fees, COGS, vouchers, and fulfillment — the profit-aware number platform dashboards rarely show.

Advertising Cost of Sales — ad spend as a percentage of attributed revenue. The mirror of ROAS.

Cost of Goods Sold — the unit cost of getting a product to the seller. The number every margin calculation hinges on.

Revenue minus all variable costs of selling one more unit — the profit each sale actually contributes after fees, ads, and fulfillment.

The platform's cut on every order — commission, transaction, and seller-funded promotions. The largest hidden line item for most sellers.

Inventory hitting zero on a SKU customers want to buy. Lost revenue, lost ad spend, and a silent ranking penalty.