I just noticed that an e-book I reviewed here some time ago, Agatha H and the Airship City by Phil and Kaja Foglio, is currently being offered as a free Kindle e-book. (Barnes & Noble and Kobo do not appear to be following suit; the book is still $8.19 for the Nook or $7.69 for the Kobo (or $9.99 DRM-free from Kobo. Is this new, offering a DRM-free book at a higher price?). But if you want to buy it, you should get it for $6 DRM-free from Baen instead.) The book is the novelization of the first part of the popular Girl Genius steampunk webcomic.
While I copped to being ambivalent about the book in my review, I’m not ambivalent at all in recommending it for free. It’s definitely worth reading. I don’t know how long it will be offered for free, but I highly recommend grabbing it while you can!