Use one of 7 Bookbyte coupons including coupon codes and product sales for September 2018. Today's best coupon is a 8% Off promo code. When it comes to education expenses, textbooks have to be close to the top of the list. Luckily Bookbyte offers a number of alternatives to help you save money. You can rent books and return them at the end of the semester, buy books at a fraction of the cost, or sell them for some quick cash.