Need a classic? Is your shelf copy mouldy, or perhaps too many students are researching the same book? Check out the Open Library for access to many classic books available in ebook format. Unlike other free ebook sites, this one is affiliated with the Internet Archive.
Just in case there are people out there that don't use CanLit already, I thought I'd post it. CanLit is a great way to buy Canadian content in both fiction and non-fiction. You just select the appropriate package for your students and order it all at once. They will also bill the school, so you can get the books very quickly. In addition, you can also substitute titles in the packages if you already have an item, or don't think it would be appropriate for your schoo.