Since it's Tor published, they are DRM free so I cross post
The key is "Tor.com original" - all originally appeared on the publisher's site and were later published. Some are free.
See all freebies
http://www.amazon.com/s/?url=search-...sher=tor+books
http://www.amazon.co.uk/s/?url=searc...sher=tor+books
http://www.amazon.ca/s/?url=search-a...sher=tor+books
The best deal is the (still free) collection of the year (huge, 15 MB Kindle download).
Some of the Best from Tor.com: 2014: A Tor.Com Original (6 Jan 2015)
by Various Authors