Every Friday I take the initiative to search through thew newly free titles on Amazon, and to identify those that might be of interest to trans* readers, fans, and lovers. Even if you don't have a Kindle, you can still download the titles through one of Amazon's free reading applications, and covert it (if need be) with Calibre. I can tell you I do most of my reading on my iPad, using Kindle for iPad, and it works beautifully.
Please do be sure to check the price before downloading anything, though, as most freebies are limited time offers, and some are specific to certain regions.
Bimbo at the Bank: Creating a Bimbo III (Bimbofication Erotica)
Tales of Feminization 2, Bob Becomes the Sub (New Adult BDSM Erotica)
Her Futa Assignment (BBW futa on female erotic romance)
Dirty Cop Gender Swap (Feminzation Menage Romance)
Hoopstars 3: How To Be A Black Owned White Tranny GangBang Girl: Tgirl Alhena Adams Gets More Than She Bargained For When She Goes Home With A Coworker Forced Interracial Transgender Erotic Fiction