It's free to play, but in a good way, too bad the game isn't that great.
This game gives off a very good first impression; the presentation is very good and there is some decent value for a few hours of playing this free to play game.
There is no need to engage in the free to play aspects of this game, it's mostly boosts that may help a bit in the early stage of the game, but at that point you are getting a lot of free gear and citizens from quest rewards that I never felt compelled to spend any money on this game.
This game really falls apart after the first few hours, there isn't enough variety and there aren't any meaningful goals to work towards, the only real challenge is balance the resource production to facilitate your colony's expansion into more resource production...
I think this is a good advertisement to get people thinking about Fallout and the upcoming game, but if you are looking for anything with any depth this won't keep you entertained very long.