Yeah and probably for another reason too...which is its because they didnt really need to buy the human daily things like food and stuff like that because they dont need it alot...I agree more with TEAM 3DWARD17 though.
All of this answer (by Team 3Edward17) is a correct! Stephenie Meyer had hinted to this point... Alice seeing "new market trends." Plus hundreds of years of accumulation (no one would dare steal from them, ha.)
That was what i was thinking, because Carlisle is a great doctor, he's bound to make lots of money, and also, because Carlisle was with the Volturi, he probably got some of those jewels, like the one Aro sent to Bella in Breaking Dawn.