Prices like Era? What are you going to say next, have those stupid death potions like Era? A leveling system would kind of defeat part of the way Graal works, as the description of the app advertises something about not having to grind to level up and etc. There's also the problem of what would a level system even do? Levels are gained to raise stats and get new abilities, but Graal has neither, so it would be useless and mostly cosmetic.