My advice would be to stay away from using her money for selfish ends like a fast race bike or any other kind of material goods, she will lord it over you later, and if you get to liking it too much you will become a dependent sniveling little bum living off someone else, and your friends will see you as such and look down on your sorry ass. I would, however, take advantage of any resources she has that would help you advance your education because that will in the end benefit her as much as you, and it could eventually put you in the same earning class as her, and then you could make her your dependent slave instead.