This is a great money-saving move! Pick one day per month (or week) to clean out the pantry/fridge/freezer. Go over what you have and get creative to make something from it. Make soup, casserole, stir fry, whatever you can think of. If you can stretch it to a week, more power to you! It prevents older food from going to waste and saves you from a grocery run for one more day.
If you can't think of anything at all, try Supercook.com. You can put in what ingredients you have, and it will give you a list of recipes you can make!