If you're buying books, consider Powell's (
http://www.powells.com/) in Portland Oregon instead of Amazon. Advantages:
1) used books come from the same warehouse, so are included in tallies for free shipping over $50
2) Customer service ROCKS -- I forgot a silly $5.50 paperback I wanted as a Channukah filler -- so I called and they added it to my internet order so I wouldn't have to pay shipping on it.
3) Employees are well treated -- I mentioned how much I like Powell's and the very fabulous fellow started telling me all about how much he loves the job and how they're having "comfort food week" during the busy Dec. season and... [I've had friends at Amazon ... they have been somewhat less than gushingly enthusiastic.]
4) They're just a wicked cool bookstore, and even if you can't go wander stacks that make most libraries look like nada, the web service has always been VERY good IME.
5) shipping on smaller orders is reasonable : $2.99 + .99 per book.
6) I didn't get charged tax -- it's possible that I still have an old OR address in some "master" list, so I'm not sure if this is universal, but it made me happy. I hate sales tax and miss OR every time I pay it. (I won't miss OR this April when I don't have to file income tax though.)
7) Plus my sweetie did a reading there -- not only a lifelong dream, but nice that there remain places that have book readings. (Shout out to Third Place Books here too.)
8) Because of extensive used book reserves, I got 5 gift books for $64!
And, generally, I just really think Powell's seems to be the best of all the reasons for supporting small(er) companies rather than behemoths, so when I'm buying books online, I check there first.