I feel like I am keeping Amazon in business at times with the $$$ I throw their way... But their book prices are fair (and WAYYYY cheaper than Barnes & Noble) Nd they are tax free and free shipping
I like: www.bookfinder.com www.allbookstores.com www.addall.com Those three are good if you just want some decent used books.
I've been buying from buy.com recently. You can use the google checkout and get 10 bucks off any item. Thus a new book shipped comes out to like 3-4 bucks. (If you search around a bit, you can figure out how to use the google checkout again on another purchase. )
I think he is saying better online or brick and mortar store. I would say that I buy a lot of my books from amazon simply because a lot of the hardbacks I like I can't find at a b&m. I love older library of America series, for example. Also I enjoy the Modern Library books. Both series are getting harder to find at the chains. The chains also don't sell many titles from literary criticism that I enjoy so much. In fact, b&m stores are increasingly mainstream and you can't find any of the great titles I look for. Don't believe me, try to locate say, tristram shandy or heart of darkness in hardback one day. My new favorite series is the penguin classic softback titles. Man, they are really coming out with some cool books. I recently picked up an anthology of russian short stories! How cool.
I usually buy used books via Amazon. They redirect you to other places that have them and rate them based on what kind of shape it's in and how soon you will get it, etc. Can't remember the last time I paid more than $5 for a book.