http://www.gamespot.com/articles/evolve-goes-free-to-play-for-pc/1100-6441572/
Developer Turtle Rock has announced that co-operative shooter Evolve will now be free-to-play on PC. The news was posted on the official Evolve website, and follows on from speculation that the game would be switching to a F2P model after the studio teased a big announcement for tonight.
Turtle Rock has confirmed the game will also be updated with various tweaks and changes. A list of some of these can be found below.
We’re reworking the hunter classes to make the team less reliant on having experienced trappers and medics.
We’re making improvements to the maps and UI.
We’re improving load times, overall performance, and getting you into the game faster.
We’re focusing on improving stability and fixing bugs.
We’re completely reworking our progression system and tutorials.
We’re adding more customization options.
Those who purchased Evolve will be granted "Founder" status in the new free version, and all the content already owned will stay. Players with the Founder status will be granted "gifts, rewards, and special access."