Baen Publishing has a free on-line library of books you can download to any reader application, including Kindle and Nook, even RTF. This is the group that publishes my new favorite author, Larry Correia (Monster Hunter International, Monster Hunter Vendetta).
So far, they are pretty Buck Rogers type stuff, but lots of military and guns thrown in too.
Hey, they're free...
http://www.baen.com/library/Also, cannot recommend MHI and MHI: Vendetta HIGHLY ENOUGH. Not only are they both just a great read, they are fun and witty and very entertaining. LOTS of gun stuff - not enough to make you skip parts but enough to make you know that the guy (a former merchant of death, aka gun dealer in Utah) knows his stuff. Note also that he lived in BHM for a while, and in the book, the hot chick and head monster killer has two degrees from AUBURN. Here's a quote from him on Character Development - the man is spot on...
Sometimes a little factoid of a main character will end up on the page. Julie Shackleford went to Auburn. Why? Because I said so. That ended up in the book, and apparently Auburn fans were pleased. Alabama fans were unreachable for comment because they were busy rolling my car over and setting it on fire
In specific, I was very pleased and I wrote and told him so.
Here's Larry's blog -
http://larrycorreia.wordpress.com/He is a very politically conservative guy (Mormon gun nut from Utah - duh) and he writes really well. I enjoy pretty much everything he writes. He and another guy are co-writing a project based on this on-line story they started a couple years ago on a gun nut blog. If you don't mind sifting through 55 pages of forum, it is a GREAT read - a thief and a mercenary and some totally awful bad guys. Middle Eastern and Africans guys getting blown up and a hot chick who can carry her own weight with a gun.
http://www.thehighroad.org/showthread.php?s=5c069ac46a69be50fdce9f8a14caeef5&t=207390&highlight=nightcrawler+lorenzoSo anyway, to sum up... Free. Great Books. Terrific new author.