I've been buying quilt books from Edward R. Hamilton for years and you can really find some good bargains. I've gotten brand new books for as little as $2.95, though most are a little higher. They charge a one time shipping & handling fee, no matter if you buy one or ten books. Also they ship very quickly. I've been very pleased with the products and services from this company and have never had any problems with any of my orders.
Oh, and they also have books on every other subject imaginable, so don't limit yourself to just quilting for the great prices!