https://www.gamespot.com/articles/rainbow-six-siege-is-free-to-play-for-a-limited-ti/1100-6456620/

Ubisoft's Rainbow Six Siege, the excellent team-based tactical shooter, will be free to play next weekend as part of a limited-time event. Everyone on PS4, Xbox One, and PC can play completely free from February 15 through February 20.

If you decide to buy the game after the free play weekend wraps up, you might be happy to know that all of your progress will carry forward. Another nice thing is that Siege is currently marked down on all platforms, so you won't have to pay full price, either.