100% thats the only way to stay in the game after lvl 100. you can decide how many dollars you want to invest in the game at that point. Even if you are all in the expense of gearing up a toon takes time( for me) so i level where i can while i build up the gear to move on..
The game gets serious after level 100, you really do have to decide if you want to spend the money to continued the game at that point. Even if you decide to spend the money to continue past level 100 it takes time to gear up.
wow sorry if this doesnt mike sense im a little drunk.