Buy all your college textbooks with cash, hold onto the receipt. Go back into bookstore with your receipt, and pick up another copy of all of the textbooks you had bought, then go wait in line. When you get to the register, pull out your receipt and ask if this is where you return books, as you had to fully withdraw from the semester or something. They'll usually say no, and that returns are out in the hall or somewhere else. Politely thank them and walk out with your stolen books, then return them for cash. At the end of the semester sell the ones you had at home back. You just made money on college textbooks.