Have you heard of the "envelope system"? Or maybe you've heard it called "cash system." My husband and I have been using the envelope/cash system for years now for our groceries, eat out, and spending money. It has helped us save money . . .
Julia at The Frugal Find has a great article on this system. She uses it for more categories than I do personally, but I think her system is great. I know it sounds hokey that using cash will save you cash, but I can personally attest to the fact that it does! Try it out - what have you got to lose?