Prices reflect information.

“In a free market economic system, prices are knowledge, and the signals that communicate information. Prices are not simply a tool to allow capitalists to profit; they are the information system of economic production, communicating knowledge across the world and coordinating the complex processes of production.”

— Saifedean Ammous

Prices are the coordinating force of a free market system. Each individual decision-maker can rely on the prices of goods and services to help with their decision making, as the prices themselves are a distillation of all known market information into a single metric. In other words, the compression of all relevant data is ultimately manifested as price (for the more technie minded, it’s a one-way hash function).