On the website you are able to customize your recommendations with genres that interest you and get a daily email about titles that are available at low cost - usually for a limited time. Personally, I will not spend more than $1.99 on a title - $2.99 ONLY if it is one that would cost me much more to check out through the Inter-Library Loan System from OPL. I have gotten so many titles for free, even titles that have been lingering on my Goodreads to read list for ages, mainly because OPL does not have them and I can't afford to use ILL on a regular basis.
www.bookbrag.com is another website that operates much in the same way. I have not had as much luck with that one though, as it seems geared more towards fiction. I rarely find a non fiction title I am interested in, but I continue to peruse it anyway.
While I am always fond of new books, of being the only owner, of not having books covered in the previous owner's cat's hair, etc. I know I read far too many books to ever be able to afford to feed my habit. So, I am on a first name basis with many librarians at my favorite branch in OPL - Swanson. So is Eleanor, too. And while I try to keep her corralled in the children's section, luckily the librarians think nothing of it when they see her streaking like a bolt of lightning across the tiled floor to hide among the stacks.