For all the world's focus on modern ideas and thoughts, often the same advice that our grandparents followed is still appropriate for our world.
Today, CreditLoan did an excellent article (Buying Food: Grocery Shopping Tips from 1950) based on a 1950's Home Economics (Buying Food) movie about grocery shopping. While the tone is dated and very sexist, the core concepts are still solid.
- Use a shopping list. I am hugely in favor of shopping lists (and menus) because I know I spend more when I don't have one, plus more food gets wasted because I didn't have a plan when I purchased it.
- Compare unit prices, but don't buy more than you can use. I find this to be particularly true as we approach a move - how much mayonnaise can we use before we leave? I hate giving away loads of food because I didn't plan well.
- Consider different forms of the same food: fresh, canned, dried or frozen. Sometimes one form is clearly more appropriate for your meal, sometimes it just doesn't matter. Frozen has great quality and a good price but canned is usually the most inexpensive.
- Purchase quantities when the price is good. Of course, this requires that you know your prices. Don't stock up unless you're sure the price is right.
- Buy in-season fresh fruits and vegetables.
- Learn to cook!