books and bargains

Library Thing tracks your home book inventory for you. Enter books by title, author, or ISBN. Listing up to 200 books is free, over that requires an upgrade to an inexpensive premium package.
BookBurro is a Firefox extension. When on a page for a certain book, activate BookBurro to search sites ranging from Amazon (including Amazon Marketplace) to BookMooch and PaperbackSwap to find you the best deal!
SuperFiller helps you find something for $4.16 to qualify for Amazon.com’s Super Saver Shipping. Also handy is the related Amazon Discount Table which filters each Amazon category by percentage discount.