Price
From the Simple English Wikipedia, the free encyclopedia that anyone can change
A price is a value people think something is worth. This is usually measured as money.
Let's say Peter Griffin raises sheep. Sally raises ducks. Winter is coming, and Sally wants some sheepskin coat to make her feel warm (although she could warm up by snuggling under Peter's fat). She could now first calculate how much sheepskin she would need for a coat. Lets say she needs 2 sheep skins for that coat. She would then go to Peter and ask him, how much he wants for the two sheep skins she needs. Peter would then likely tell a price. Alternatively Sally could trade some of her ducks for the sheepskins.
Since trading ducks for sheep is rather complicated, people introduced something they called money. This is simply used for trading. So sally would trade some of her ducks for money. Some of this money she could then give to Peter to get the sheepskin. The same thing is happening in the real world,the only difference is that every factors mentioned above is bigger minimum five times.