Commutative justice is dependent upon the guideline of the prevailing price. Without the prevailing price as the bench mark, one cannot determine which individual price and contract satisfies the demands of commutative justice. If the individual price is subject to (individual-)ethical norms of justice and fairness, the standard of the individual price, the prevailing price, must satisfy ethical norms. Since the prevailing price in a market economy is the market price, the market price, as the standard of individual actual prices, must also satisfy ethical and social-ethical norms.