At the beginning of the month when you go to the grocery store, use your credit card to buy store gift cards and use them to buy your groceries for the month. On the receipt it shows how much is left on your card, hopefully keeping you within budget. If you get close to the end..
..you may not buy things you really don't need, or you may have money left for the next month. Using the credit card to buy the store cards may get you some perks from the credit card. You then can send a payment to the card company. : ) Isn't on-line banking great!!