Producer Surplus. Producer surplus is the difference between the price producers are willing (and able) to supply at and what they actually receive. Producer surplus is the area between the market price and the supply curve.
The supply curve shows the minimum price producers are willing and able to accept to sell different quantities of a good. Producers are willing to sell at a low price for the first unit but a higher price for each extra unit they sell. Although, producers receive the market price P* for each unit.