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.
The Androgynous Andromedan (The Alien Sex Chronicles Book 9)
The Hermaphrodite Captain! (Bisexual Threesome Alien Erotica) (Space Hookers Book 2)
The Fappening - Celebgate: Femdom Humiliation Erotica
Mall Cop Gender Swap (Gender Transformation Erotica, Feminization)
The Futa's Billy Club (Futa on Female Erotica)
My Futa Cybergirl!
The Demon's Plaything and the Pixie Punk: A Gender Swap Tale (My Infernal Mistress Book 2)
Nerdy Girl, Part 1: Gender Swap Erotica
The Futa Feline (Paranormal Futa Erotica)
Gender Switch, Genie's Wish! (Gender Swap Erotica)
A Guy's Surprise (Gender Swap Erotica, Three-way)
Twisted Mister! (Gender Swap Erotica)
Sex and the Sissy 2: The 1960's
The Cougar's Surprise (Transsexual Erotica)
Shipwrecked Shemale! (Transsexual Erotica)