Revenue is not profit

The number on a sold listing is only gross buyer-paid revenue. A useful decision starts after subtracting the costs required to acquire and complete the sale.

Net proceeds = buyer-paid revenue − marketplace fees − seller-paid shipping − packaging − other variable selling costs.

Net profit = net proceeds − purchase cost, also called cost of goods sold or COGS.

Unknown costs should stay unknown until you can verify them. Do not insert a marketplace fee from memory or assume shipping is free simply because the buyer paid a shipping charge.

Margin and ROI answer different questions

Profit margin compares profit with gross buyer-paid revenue. It asks how much of each revenue dollar remains after recorded costs.

Inventory ROI compares profit with the money invested in the item. It asks how hard the purchase capital worked.

An item can have a healthy margin but still tie up money for months. Another item can have a smaller margin but turn quickly and return cash sooner. Neither measure should stand alone.

Price from the break-even point outward

Break-even price is the sale price where recorded proceeds exactly cover recorded costs. It is a floor, not a target. A target price should also account for the profit you want, the time and uncertainty in the sale, realistic demand, and the condition of the item.

If a fee is percentage-based, it changes as the sale price changes. Solve the fee inside the break-even calculation instead of subtracting a fixed guess.

Include the costs people forget

• Purchase cost and landed cost

• Marketplace percentage and fixed fees

• Seller-paid shipping

• Packaging

• Other sale-specific variable costs

• Refunds, returns, damage, and loss when they actually occur

Your time and overhead can matter too, but keep them separate unless you have a consistent method. Mixing an arbitrary hourly value into every item can create false precision.

Stale inventory has an economic cost

Unsold stock occupies space and keeps cash unavailable. Review inventory age alongside asking price, expected profit, and sell-through evidence. A controlled markdown can be rational if it releases capital for a stronger opportunity; a panic discount without updated numbers is not a system.

Use a repeatable decision loop

1. Record the actual purchase cost.

2. Estimate a realistic sale price without treating the best active listing as proof.

3. Enter verified fees and selling costs.

4. Compare net profit, margin, ROI, and break-even.

5. Decide whether the expected return justifies time, risk, and capital.

6. After the sale, replace estimates with actual results.

Run the free reseller profit calculator, then learn how to calculate real reseller profit and how to price items for resale. Flee OS can carry the same logic into your actual inventory history without changing financial truth from an AI guess.