Seller guide
Did my eBay discount create incremental profit or just discounted sales?
Reconcile eBay Discounts Manager base, promotion, and total sales, then test whether supplied margin can cover the discount without treating attributed sales lift as proof of incrementality.
Freeze the completed discount report and comparison window
Use one eBay marketplace, currency, completed discount, and reporting window. Keep promotion ID, type, base sales, promotion sales, total sales, reported lift, total discount cost, items or orders, and the report generation time together. If you add comparison-period sales, use an equal-length period with documented stock, price, advertising, and seasonal differences. A nearby date range is not automatically a valid control for the promotion.
Reconcile the report components before modeling profit
Calculate promotion-sales share as promotion sales divided by total sales. Separately compare base sales plus promotion sales with reported total sales, and compare promotion sales with any supplied reported-lift amount. Preserve nonzero differences as source-data exceptions rather than rewriting a component to make the identities balance. Report definitions, aggregation, timing, and rounding can differ; the arithmetic identifies the mismatch but cannot select its cause.
Start with the most generous incrementality assumption
As an upper-bound test, multiply promotion sales by the seller-supplied gross margin percent, then subtract the supplied discount cost. This asks whether the discount could contribute even if every promotion-attributed dollar were truly incremental. Divide discount cost by promotion sales for the break-even gross margin. If the result is already negative under this generous assumption, a stronger causal claim cannot rescue the submitted unit economics.
Use an equal comparison period as context, not proof
Subtract supplied comparison-period sales from promotion-window total sales, flooring the observed increase at zero, then apply the same gross margin and discount cost. Show that comparison-based incremental contribution beside the all-promotion-sales upper bound. Stockouts, price changes, advertising, product mix, seasonality, competitor moves, and marketplace attribution can explain the difference. A before-and-after window improves context but is not a controlled experiment.
Rank losses and thin headroom before repeating the discount
Separate promotions that lose money even under the generous assumption, those whose comparison window reveals a loss, those with thin positive headroom, and those with no activity. Verify current costs, returns, fees, shipping, and report scope before a human plans another discount. eBay's reported sales lift does not prove those sales were incremental. Friday reads no eBay account or buyer data and never creates, changes, pauses, resumes, or publishes a discount or listing.
Tools that help with this
Prices below are exact x402 per-call prices. Human card checkout uses fixed $3, $9, and $29 bundles; follow a tool page to see its applicable bundle.
- eBay Discount Sales-Lift Margin Reality Check ($0.50) — Reconcile report components and test upper-bound and comparison-period contribution
- Coupon and Deal Incremental ROI Calculator ($0.25) — Run a broader seller-supplied baseline-versus-deal contribution model
- Marketplace Promotion Profit Guard ($0.25) — Screen a prospective discount scenario before any human activation
Every paid output is a draft for your review before you publish, appeal, or activate anything. Friday does not access your seller account.