Manage costs for a quiz bowl team

You're the captain of the quiz bowl team and you're finding that not everyone on the team takes it as seriously as you do. Your attempts to drum up support for practices have fallen flat in the face of the casual attitude of your teammates, an attitude that's showing in competitions. You want to bring a sense of pride to the team, so you decide to pitch the idea of T-shirts. This gets your teammates attention. They're in, but you'd like an easy way to collect money from them that doesn't involve harassing them at meets.