How does rake work?

Let's say it's a 1/2 table, and button goes all in(200 dollars for the sake of the question). SB and BB folds, button wins the pot. Will there be a rakeback for the whole pot (203 dollar pot), or will it only affect the sb and bb? I mean, if it affects the whole pot including the all in, then you'd probably end up with less than you had to begin with

Someone can correct me if I am wrong, but I think most poker rooms don't charge rake if the hand doesn't see the flop. So in the case of your example there would be no rake since the Button won preflop.