In the moment, with everyone and everthing going on around her, I doubt she was thinking rationally or even knew that torching a car would be a long prison sentence. (if someone asked me before reading this article, I would have assumed a large fine + some community service maybe; then again I am not American so I have no idea how sentences compare).
Then if someone can't pay it back, you either have to 1) not penalize them, making poverty equal immunity, or 2) jail them, making it jail for the poor and a fine for the rich. Neither seems fair.