An expression referring to the role of prices in a market economy in conveying information, providing incentives, guiding choices, and allocating resources. The ‘market mechanism’ is an alternative phrase with the same interpretation. The prices people are willing to pay for goods and services convey information about how much they value them, and the prices producers ask convey information about how their inputs are valued. The price mechanism provides incentives to allocate resources where their value is highest, and to satisfy wants from the cheapest sources.