If you have a specific book you want to buy, run it through this book shopping and price comparison search engine, AddALL.  Plug in your ISBN number [you can find that on Amazon] or the title, and enter in your shipping state, and you will get a list of results sorted by price [including shipping].  The site searches over 40 book selling sites and thousands of sellers.  Great way to find the best price on a book rather than just going to Amazon or the other big bookstores.  You can search by Title, ISBN, keyword and author.