Amazon cuts up to 90% off new and used textbooks and etextbooks. (Prices are as marked. You'll bag even greater savings if you trade in your old books.) Plus, Prime members receive free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, it starts at around $5.) That's the first such discount we've seen on textbooks from Amazon. A Kindle or Kindle-enabled device is required to download and read the etextbooks.