Donate your body to science. I participated in a flu study at UVA to pay for summer classes. I made $3,000 for a week's work. They put us up in a nice hotel, had meals delivered to our rooms, and injected us with influenza. I didn't contract it, made some interesting friends, and caught up on all my reading and intense movie-watching. Check all your local hospitals, med schools, and clinics - they're always looking for study participants.