In economics, market price is the economic price for which a good or service is offered in the marketplace. It is of interest mainly in the study of microeconomics. Market value and market price are equal only under conditions of market efficiency, equilibrium, and rational expectations.
On restaurant menus, "market price" (often abbreviated to m.p. or mp) is written instead of a price to mean "price of dish depends on market price of ingredients, and price is available upon request", and is particularly used for seafood, notably lobsters and oysters.
References
Market price Wikipedia(Text) CC BY-SA