Wait until endgame. Then you'll have to buy stuff.I am playing RoM at the moment, and I can say that this game really is free when you compare it to the other "free" mmo's.
I have been playing for several months now, and only thing that you want to buy is mount (about 10$), and you dont have to buy mount eather, because you can rent it for ingame gold.
I have not yet reached end game, but so far it looks like real "free to play moo".
But it's still a good game. I hate the graphics though...