Stumbled upon this site for free books. All the ones I looked at here are Free, which would make sense as the name of the site is Books Should be Free. There are kids books, Young Adult, and classic Literature (think Pride and Prejudice) and a ton of other options. I loved flipping through the options here. Some History ones that I can't wait to dive into.
Books Should Be Free
I also visited The Story Home and they have some great audio books as well, but most of these are .99 each and not free, but its great to have some choices. Some of the stories I saw included ones from Beatrix Potter, Charles Dickens, The Brothers Grimm, and many other classics, both short and long.