My local library has 2 or 3 book sales a year. Because of their excellent used bookstore, they get more books donated that can be sold through the store. The overflow is sold in a large sale to benefit the Friends of the Library. That means ultimately it benefits the library.
Today was the spring sale of the year. I volunteered to work opening this morning. Of course the first thing I did was look over the huge selection. With all hardbacks and trade paperbacks only 50 cents and mass market paperbacks a quarter, it's hard to resist. I walked out with 11 books. Only one was for my daughter although I was looking for other titles for her. I've read one of the other books I bought. So that means 9 more for Mt. Bookpile. (I only took 2 off this week.)
Friends of the Library book sales - dangerous. No wonder my Mt. Bookpile shelves are overflowing.