What was unique about Junior's prom experience?

Junior goes to Winter Formal with Penelope, and because he doesn't have any money, he has to meet her at the gym. He can't pick her up, because he doesn't have money for gas or the ability to borrow or use his family's car (Alexie, 121). Additionally, because of Junior's financial situation, he has to borrow and wear one of his father's old suits from the 1970s. Although at first he is embarrassed about this, Penelope acts like the suit is cool and retro. Junior feels proud and excited and does some disco moves to make everyone laugh (Alexie, 121–122).
A group of Junior's friends goes to a diner after the dance. Since Junior doesn't have any money, he panics at the end of the meal and goes to the bathroom to be sick. Roger finds him and discovers the problem. He gives Junior the money to pay for the meal, and when he and Penelope discover that Junior is poor, Roger drives both of them home at the end of the night (Alexie, 125–129).