Shopify's native profit reports snapshot cost at sale, while Cost per item remains one current value. CostLedger adds a merchant-controlled dated receipt ledger with moving-average math you can inspect. Record receipts by hand, CSV, or completed Shopify PO PDF. Review included and excluded amounts before recording. CostLedger never overwrites Shopify's Cost per item. Use its 30/60-day margin reports, estimated monthly COGS, inventory valuation, alerts, exports, and guarded receipt reversals.