Your Purchase Cost Rose. What Profit Will the Next SKU Sale Leave?
The new inventory batch costs more, but the marketplace listing still carries the old selling price. Replacing one cost value with another can make the history hard to interpret: yesterday's sale and tomorrow's order may relate to different purchases.
For a management decision, separate profit on units already sold from the expected contribution of the next batch. Statutory inventory and tax accounting rules are a separate matter. This example tests a business decision; it does not prescribe an accounting policy.
Keep two cost snapshots
For each receipt, record the date, quantity, unit cost and any expenses included in purchase cost under your chosen method. Keep the original document. Do not overwrite the earlier entry merely because a supplier quoted a new price.
Illustrative example: an older batch contains 40 units at ₽420 each; the next contains 40 at ₽560. After marketplace fees, logistics and attributable advertising, a sale leaves ₽700 before purchase cost. The older unit contributes ₽280 and the new one ₽140. Neither figure is net profit: taxes and other costs have not been included.
That ₽140 difference explains why an existing promotion or ad bid needs review before the next batch sells. All figures are hypothetical, not a marketplace tariff or customer result.
Match a sale to the cost rule and period
In one control sheet, keep the SKU, sale date, marketplace statement period, batch balances and your cost-allocation rule. If you use an average cost, show the calculation and its effective date. If a specific batch is identifiable, do not silently replace its cost with an average for the sake of a tidy chart. Mark the result provisional when the evidence is incomplete.
Late returns and adjustments matter too. They may alter a previous period after a new purchase price has taken effect. Compare like periods and sources so that a cost change is not confused with a new fee or advertising charge.
Decide before the next sale
For the new batch, test three scenarios: today's selling price, the planned discount and the price that meets your minimum contribution after variable costs. Then assess demand and marketplace constraints. A correct calculation does not guarantee that a price rise will preserve sales.
Start with unit economics for a single marketplace sale. This guide adds the time dimension: which cost was known and applicable when you made the decision?
ProfitVena helps inspect SKU profit using configured costs, available marketplace data and supported Excel/CSV imports. Completeness depends on connected sources, product mapping and your cost rule. It does not automatically identify a sold unit's purchase batch without reliable source data. The technical part was updated in ProfitVena. ProfitVena is part of the Виксора ecosystem.
