Star Wars Battlefront 2 is free for a limited time on the Epic Games Store. The game normally costs 39.99 euro but for the next seven days you can get it for free. The offer ends on Thursday, January 21.
To get the game, just go to the Star Wars Battlefront 2: Celebration Edition page on the Epic Games Store, and click the "GET" button. Once you get the game, it will be yours forever.