Jason had his own problems to worry about. Even if he managed to steal a new Prius from some douche, it wouldn't be enough. Only one of the crime bosses could afford a Maserati like the one that Bruce Wayne had multiples of. Besides, he probably had enough security to make a whole team disappear. He'd probably be better off robbing a bank or someone like Batman.
Who would be crazy enough to do something like that?
Then again, if he got caught, the street cred might be enough to convince Jim to hire him back after he got out.