The price mechanism is the means by which decisions of consumers and businesses interact to determine the allocation of resources.
The free-market price mechanism clearly does NOT ensure an equitable distribution of resources and can lead to market failure.
Changes in market price act as a signal about how scarce resources should be allocated.
A rise in price encourages producers to switch into making that good but encourages consumers to use an alternative substitute product (therefore rationing the product).
A fall in price leads to an extension of demand but makes it less profitable for a business to supply the good or service affected.
One important feature of a free-market system is that decision-making is decentralised, i.e. there is no single body responsible for deciding what to produce and in what quantities.
This is in contrast to a planned (state-controlled) economic system where there is significant intervention in market prices and state-ownership of key industries.