Sam bought some apples by the pound. He sold half the apples for 50% more per pound than his purchase price. He then sold half of the remaining apples for 25% more per pound than his purchase price. He then sold the remaining 650 pounds of apples for 25% less per pound than his purchase price. If he had $2600 in total sales, what was Sam's purchase price, in cents per pound, for the apples?