Granted, a store should recover its costs for shipping, but at these rates shipping becomes a profit center. They require you to first find the ISBN number for all of your books and then enter these numbers in a special search form. That is somewhat cumbersome, and the links don't place all the books into your shopping cart, just the last one you entered. As I said, lots of programming is required to get this sort of thing right. Chances are I'll probably just go to the store's site directly to make multiple book orders.
Comparison shopping on the web has lots of promise.
But you need to pull off great searching and database technology along with solid site design to make it really fly. Commerce Suites can help your company sell on the web, but be aware they're still immature. It includes tests on several eCommerce suite products done by Client-Server Labs.