Field notes / seller economics
Short guides for the next margin decision.
Each guide connects one practical seller question to a transparent formula and the calculator that can test it.
Seller economics / contribution margin
Contribution margin, one order at a time.
Learn how to calculate ecommerce contribution margin per order and use it to set an ad-spend ceiling.
Read guideSeller economics / returns
Your margin after the return arrives.
See how return rate and per-return loss change ecommerce profit margin, with a transparent order-level model.
Read guideSeller economics / pricing
Price backward from the margin you need.
Work backward from product costs, marketplace fees, and a target margin to find a defensible minimum selling price.
Read guideAdvertising economics / ROAS
Two ROAS thresholds, two decisions.
Understand the difference between target ROAS and break-even ROAS using product-level contribution economics.
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