Amazon.com totally started clicking for me (a longtime Powells snob) when they began offering used books rooted out of the back shelves of bookstores around the country. Today, for example, I am reading Samuel Abt's hard-hitting critique LeMond - The Incredible Comeback of an American Hero. Smooooch! [Actually, the book works well as a really long interview.] Why am I reading this? Because the Tour is coming, and because Amazon sold it to me in hardcover for $1.00 from a bookstore in California.
If you're not already in the habit of doing so, I recommend browsing the stacks in Amazon's Cycling section, and look for those bargain prices. If this link expires, the section is Books-Sports-Individual-Cycling-General. BTW, Floyd's new book is already marked down 25%, and isn't out just yet. Oh, and It's Not About the Bike will run you $0.01, plus shipping.