Re: Book Renter, obviously it works differently in the USA. When I went to university (in Canada) teachers were insisting on the new edition every year (I'm guessing the publishers sent them free copies). The only thing that changed was the colour of the graphics and the order of the exercises. But it's enough to make the student's life difficult if they're using a different edition. Our university bookstore tried to buy-back and re-sell text books, but obviously they only did that when edition wasn't changing and there was a market for used books.