I just came back from the Public Library. They had a sale on discarded
books. I think it had been going on for a while...but anyhow, I bought 55
books for "ten cents" each! I'm planning to have my students used them next
year for "altered books".
Also, at the end of the year our library at school had a stack of discarded
books and I was able to get enough for my students for last semester.
A lot of times, school libraries clean out at the beginning of the year.