Peanut butter is a must for any frugal pantry. It keeps for at least six to nine months, so you can buy it with a coupon or when it's on sale and stock up. It's really a pretty versatile food item. Aside from every family's favorite, the PB&J sandwich, you can add it to a banana or apple slice for a grab and go breakfast. You can also use it when you're baking and in other recipes as well. Add a spoonful to your next Asian noodle bowl and you've got peanut sauce, or use it in your marinade for chicken or beef kabobs.