Marginalism just means that the specific, concrete good or thing as the object of choice is the object of people's action and therefore valuation. Marginalism d

Marginalism just means that the specific, concrete good or thing as the object of choice is the object of people's action and therefore valuation. Marginalism does not require having a market price, but quantitative calculations of accounting magnitudes, like profits, losses, cost, revenue, do require market prices.