After announcing Linux / SteamOS support for the latest Unreal Engine 4.1 about two weeks ago, a recent announcement posted on the Unreal Engine wiki mentions that the next Unreal Tournament game will be "not free to play, just free" and it will be available for Linux as well as Windows and Mac:
"Work on the future of Unreal Tournament begins today, and we're happy to announce that we're going to do this together, with you. We know that fans of the game are as passionate about Unreal Tournament as we are. We know that you have great ideas and strong opinions about where the game should go and what it should be. So let’s do something radical and make this game together, in the open, and for all of us. [...] Development will be focused on Windows, Mac and Linux".
Epic Games plans to make money by creating a marketplace where developers, modders, artists and gamers can give away, buy and sell mods and contents and the earnings will be split between the content developer and Epic.
It will take a while until the game is playable since the development starts from scratch, but an Alpha should be available in a few months.
Read more about this HERE.