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.
His Secret Desire (A Threesome Erotic Romance Short)
Kit Treats Him like a Girl #1
A Man no More: How Victoria Feminized her Boss
Taking Her Young Man From Behind (MILF Diaries #2): A Naughty Femdom, Hard and Deep Tale
Dominatrix: Candid interviews with 20 real life Dominatrixes (Volume 2)
My Life as A Mail Order Bride
Nursing the Futa Boss (The Futa HuCow 1)(Futa-on-Female, Nursing, Creamy Treat, Domination)
Tender Gender Bender Transgender Romance
Cynosure Illustrated Fiction
Bitten And Swapped: Gender Swap Vampire Erotica
Varsity Domme: FemDom Unleashed
SISSY MAID in the mirror (a sissy maid missy sister series Book 3)