Use generics. From medications like Tylenol (acetaminophen) and benadryl (diphenhydramine), many are exactly the same as the brand name, and always a LOT cheaper. They work the same, and a lot of time they are made by the same company. The same goes for food. Many are just as good.
Most of the generic brands are just as good as the name brands, although a few are not. It is a trial and error thing and depends on taste. Some things, like toilet paper, I haven't been able to find in the generic.