Okay, I'll apologize up front if this isn't the right place to post this, but I figured that since most of the ebook (Kindle, Nook, etc.) discussions seem to crop up in this forum, I'd post it here.
Anyway, if you have an e-book reader like a Kindle, Nook, Kobo, iPad, iPhone, etc., this website has a list of some of the best sites where you can find tons of free ebooks:
Going FREE! Kindle eBook Promotional Campaigns for Authors
The above blog post is actually geared more toward authors who want to make their books free, but it's also a great resource for readers who are looking for freebies.
And remember that you don't actually have to own an e-book reading device to take advantage of free or inexpensive e-books. There are free apps for computers, tablets, and smart phones for the Amazon Kindle, Barnes & Noble Nook, along with iBooks, which you can use on your iPad, iPhone, or iPod touch.
Enjoy!