I'm a librarian who loves anime, manga, and reading a wide variety of genres.
I don't generally read Kindle books and I already own almost all of these either in e-book form or in paperback, but I got them anyway. Free is nice, and I could see myself rereading them while waiting in line at the grocery store. Also, I used my "purchase" of the Kindle version of Binary Witness to get the audibook for $1.99 on Audible. I've been wanting to listen to it for a while, and since it's an Audible Exclusive, I don't think it's possible to ever find it in Overdrive.
If you don't know about this series, it stars an agoraphobic hacker and the ex-con who manages to convince her to let him clean her house and occasionally make her something to eat.