Sales
Many people have this notion that if anything is on sale either it must be spoiled or going out of style.
While this is true in many cases there are also sales that are not of this type. A great example of this is introductory sales.
Introductory sales are the perfect place to buy great yet dirt cheap products, whether these be clothes or food. If the product on sale is not perishable, like clothes and shoes, then buy as many as you need for the year/season. You will end up dressing up in style at a low cost.
If the stuff on sale are food items check the expiration day and stock up depending on how much of that you estimate you’ll be consuming a full month or two before the expiration day.