Start small. Take a $100 bill and put it in your wallet, and don't spend it. See if you can leave it in there fr a month. If that works, bump it up to $200. the point is to be able to understand that life goes on even if you don't spend the money on that thing you want. Hell, start with $50. ANy amount will do, just tell yourself not to spend it no matter what. If you can do this for three months straight (keep $100 in your wallet) I guarantee you you will have a better understanding of money and you won't be impulsive.