You can't change the parents but you can help the kids. I've felt burned before when I went out and bought bookbags, clothing, etc. for students in my class and then I see them being picked up every day by their mother in the Jaguar or the Range Rover or the parents that come in with more gold than Mr. T and Gucci sneakers, but their kid wears the same dirty uniform shirt for a week.
However, it made the kid feel better when I replaced the bookbag that was hanging together by the last string and that's all that needs to matter for me.