When my husband and I find ourselves putting more prepared foods and snack foods in the grocery cart than we probably should, we challenge ourselves to stick to the "5 ingredients or less" shopping plan.
"Challenges" work well for us because we are both all-or-nothing type personalities, so just trying to cut down doesn't really work for us.
- don't buy junk food. There's no nutritional value and one can sit and eat it forever (I.e chips)
- buy staple items. I never buy for specific recipes because you'll buy a bunch of ingredients that will go bad before you can use them again.
- compare price per oz/lb. when shopping. Especially withb fruit. Some weeks frozen fruit might be cheaper than fresh.
- if there is a SUPER SALE on an item, stock up and freeze what won't be used immediately. Lastly, in some tates foodstamps can be used at the farmers market and they'll match you up to $5. So $10 worth the fresh food for $5 in stamps. Go near closing time because a lot of stands will reduce their prices to sell it quickly.
Making a challenge to ourselves and sticking to it for a few weeks or months helps us to re-set our shopping and eating habits.
We goe through $150-200 of groceries a week, and we seldom eat out. But that's eating comfortably, not frugally, and we're no longer using our time clipping coupons or some of the other excellent suggestions here - I just wanted to give a point of reference.
Using the same grocery store for a while has helped - I know which items they tend to put on sale, like Life cereal that will be BOGO every 2 months or so, or one of the brands of laundry detergent, so I can wait until those sales come along.
If you are doing most of the cooking answer: what are you generally preparing for breakfast, lunch and dinner?