Tribes Ascend is an example of a great Free to Play model game. As long as it is not Pay to win, free to play is a great model. Some people have money, and some people have time. This model lets them all play so the game will have a huge population. The people that pay will have more people to play with making their purchase well worth it. If it is done well, a player should receive the entire contents of a game for the same $50-60 that they would spend buying that game.