I've "bought" 85 books from Amazon.com, though 36 of those were free books. Of these books, 10 were books that I had already read in paper format and I've read 32 others so far.
From Baen, I downloaded all of the free books, and have read 6 of them. I've purchased 26 books (two of the monthly Webscription bundles, the Jerry Pournell bundle, and some miscellaneous titles) and have read 8 of them.
From Fictionwise, I've purchased 11 books and have read 5 of them.
We won't even discuss the books I've downloaded from MobileRead, Feedbooks, Manybooks, and Munseys.
There's not enough time in the day/week/month!