How does Armpit finally understand his economics concepts?

Armpit brings his economics textbook, so he can study for an exam he has later that day. Behind them are several street people who, it turns out, have been paid by a pair of professional scalpers named Felix and Moses to stand in line for them. After X-Ray and Armpit buy their tickets, the guys talk to Felix, who tries to convince them to sell them their tickets at a good price. His arguments trigger sudden insight into the economic process for Armpit.