According to classical economics, in a free market (whether monopolistic, oligarchical, or competitive) prices come from an interaction between the supply curve and the demand curves, which plot the marginal benefit vs the marginal cost of each additional unit of whatever is being produced.

How are prices formed?

The price of a product is determined by the law of supply and demand. Consumers have a desire to acquire a product, and producers manufacture a supply to meet this demand. The equilibrium market price of a good is the price at which quantity supplied equals quantity demanded.

What determines prices in the market?

What Is Market Price? ... The market price of an asset or service is determined by the forces of supply and demand. The price at which quantity supplied equals quantity demanded is the market price. The market price is used to calculate consumer and economic surplus.