Regarding money will be always a problem when you are allowed to pickpocket and the items from the vendor. If you are optimizing you will get your rogue to rob the money back of whatever purchase you did given there is no penalty doing that.
Barbarian is fine, encounters needs to be tweaked there is some arenas that actually makes casters shine much more, solved some stuff with 3 casters and my player character was just a meatshield to absorb the harm. Control Spells > Unga Bunga golden rule in DND.
