apps similar to ebook buffet

Hi all!
I have a question about ebook buffet. I'm a cheap skate and a bookworm, so as you can imagine, I'm always looking for a good deal on books. Well, I heard about this app called Ebook Buffet, and thought I'd try it. But, I looked, and the dev hasn't updated it to be compatible with ios. 11. So, I was wondering if there were any similar apps? Thanks in advance.