Unfortunately, this means if you're keen on getting hold of Fallout 3 for free you're going to have to pay the full digital price for the game, which is $59.99 / £59.99.
The first Fallout 4 details were announced last month at Bethesda's E3 conference, but Bethesda saved some news for the Microsoft conference, including cross-mod support between PC and Xbox One versions of Fallout 4.