Fallout 4 [official site], completely free to play for three whole days.
That’s 100% correct, PC and Xbox gamers will be able to play Bethesda’s critically-acclaimed post-apocalyptic RPG over the weekend, without having to pay anything (except for their time). The base game and mods will be accessible, but no DLC.
PC users will be able to start downloading and playing the game via Steam at 5pm GMT tomorrow (Thursday) and the session will end at 8pm GMT on Sunday.
Xbox users who have a Gold account can begin to download and play the game at 7am GMT and the session will end on Sunday at 7am GMT.
Should you decide to buy the game over the course of the weekend, there will be big discounts on both Fallout 4’s base game and the season pass on the major platforms (including PlayStation, which it is unfortunately not free to play on for this weekend).