I don't know how many sites there are that will send you online newsletters for reduced price and free books, but I think I must belong to most of them!
It takes at least an hour just to scroll through them every day. Some days I just have to hit delete and let any good deals pass me by.
There is Book Bub, of course. Everyone's heard of it, I'm sure.
Then there are The Fussy Librarian, eReaderiQ daily, and Ebook bargain UK (but you can sign up for different countries including the USA). Add to that Ereader News Today, the Kindle Book Review, and Readfree.ly. There are also Free Kindle Books and Tips along with Peoplereads.com...
And I also subscribe to Digital Book Spot, which I don't often look at because it lists so-o-o-o many books, it takes all my allotted time!
I found these when one of my books went on sale for $.99, and I wanted to do a little advertising. Unfortunately, ads run anywhere from eight dollars to four hundred. I did put a couple in some of the cheaper sites but didn't get much of a bounce in sales.
But I certainly have picked up a lot of book bargains!!!