A barber is DEF a must. And, imo, it doesn't need any sort of a cooldown or real money. Just make it a fairly small gil cost everytime. Changing your skin color/face/etc, that could be more grounds for spending real money (even though, I still think that could still cost gil, maybe a cooldown).

I play WoW (I know ..), and the barber is prob one of the most fav things they ever added. It's just nice to be able to change up your look here and there. Really takes out the monotony.