The art of stockpiling. When something goes on sale and you have a coupon that makes it really cheap....buy more than one. I try to keep a stockpile of toothpaste, deodorant, soap and other toiletries. These are items that do not expire or go bad. I only stockpile a few months supply. Sometimes I am able to get frozen veggies on sale; then I will stockpile a few months supply.
From time to time I will go through my stockpile and thin it out. I donate to the local soup kitchen or shelter.