If you read the classics, get your copies from the MobileRead library instead of from Project Gutenberg. These are typically exquisitely formatted.
Several freebies that I've picked up from Amazon have led me to read further into the author's series. And, you may want to take a look at the really cheap (but not necessarily free) books which are the first in a series in your favorite genres. I tend to like mysteries (particularly cozies), science fiction, and fantasy. So I occasionally search for free/cheap books in those genres. I also follow the threads in the
Deals, Freebies, and Resources forum.