Are you teaching a reading class? Or a debate class? Would you like to offer your students a number of choices of free e-books instead of forcing them to buy a book?
From my own experience I know it can be extremely tiresome to browse website after website to search for appropriate e-books to share with students. This website here looks like it’s going to save me a lot of time. It’s a compilation of 50 websites with free e-books. You can browse the webliography by genre or alphabet.