I mentioned this at the end of the Kindle post, but I wasn't sure if you guys saw it and I thought it was an interesting followup to the discussion. It addresses some of the concerns about the expense and also shows how the schools get around being stuck using the same books every year. If you guys already saw it and just didn't have anything else to say, then forgive me for reposting!
I emailed my mom to remind me how it worked, and this is her response:
"The books you used were from the school. usually classroom sets purshased by the school board or the PTA. Each school district is different. Right now I know that if a teacher needs a set of books for a class and she does not have enough , all the librarians will get an e mail for interlibrary loans. There are 177 schools in Duval County. Books from other schools are checked out over the internet and sent by school mail where they are needed. I can easily see a teacher requesting students to buy a paperback but not a hardback title."