Prices are equalizers of supply and demand functions.  The more you offer to pay for something, the greater the supply of it you can get for that price.  The cheaper you offer to sell something, the more people want to buy it.

If you consider all the apples being sold inside a city, then the numbers of apples bought, and apples sold, are always equal.  So the price of apples is the price that causes the amount of apples wanted to equal the amount of apples that can get supplied.  Though, to have this always be true, you might need to include implicit costs, like, if you want a special kind of apple that takes an additional five minutes to get shipped to you, the cost of the apple is five minutes plus some copper, not just the copper.

Prices are equalizers of supply and demand functions.  The more you offer to pay for something, the greater the supply of it you can get for that price.  The cheaper you offer to sell something, the more people want to buy it.

If you consider all the apples being sold inside a city, then the numbers of apples bought, and apples sold, are always equal.  So the price of apples is the price that causes the amount of apples wanted to equal the amount of apples that can get supplied.  Though, to have this always be true, you might need to include implicit costs, like, if you want a special kind of apple that takes an additional five minutes to get shipped to you, the cost of the apple to you is five minutes plus some copper, not just the copper.