My sister got me started going to these used book sales. Four of us are going to the big Centenary Book Sale in a couple of weeks.
http://www.shreveporttimes.com/article/20100828/NEWS01/8280322/Centenary-College-s-giant-book-sale-to-return-for-24th-year
Centenary College’s giant book sale to return for 24th year
The local library had a book sale in which they were clearly just trying to get rid of a bunch. You could fill a large shopping bag full for a dollar.
I got a couple of bags full. It took quite a bit of looking but I got some surprisingly good ones including one which was full of 11X14 lithographs of famous paintings. They were all suitable for framing.