If the price of MP3 downloads rises, people might be less inclined to buy MP3 players like iPods because the cost of using them (i.e., the cost of the downloads) has increased. In this case, MP3 downloads and MP3 players are also complementary goods.

In a supply and demand diagram, the demand curve for MP3 players would shift to the left, indicating a decrease in demand. As a result, the equilibrium price and quantity of MP3 players would both decrease.