My kids love books! So every time we are at our library book store or a homeschooling thrift store, we get tons of new ones, and these trips are usually a highlight of their week!
But often we can not find what I was looking for. Sometimes we get a good recommendation for the book here on the forums or I get inspired by the list of the books I find on some homeschooling curricula, like this
http://www.sonlight.com/curriculum.html 
BTW, check these out, -- selection is great! So then we have a few websites we use to get books for much cheaper then retail, or ebay or even Amazon.
I thought to share a few of the ones we used at some time or another:
ttp://www.homeschoolbuy.com (The Old Schoolhouse Magazine's auction site)
http://www.homeschoolbuyersco-op.org (free classifieds)
http://www.paperbackswap.com or similar to it
http://bookmooch.com/http://www.hpb.com/ (Half price books, I have not used it myself, but my friends use it and like it)
http:// alibris.com -- used it lots of times and never was disappointed!
http://www.homeschoolclassifieds.com/ -- Great place to find homeschool curricula, books and even other manipulatives!
http://classifieds.theswap.com/ -- this is neat website, if you check it often enough you can find all kind of great early learning/homeschooling materials
http://www.vegsource.com/homeschool/ - there is a decent homeschooling section here
Also curriculum supplies sometimes have forums where you can find their curriculums second hand, like these ones:
https://forums.sonlight.com/http://www.winterpromise-forum.com/Hope these ideas help! Please share yours.
Digg
