Okay. Having read more than my share of frugality blogs, I know a lot of people save money on the grocery budget by planning menus around the sale flyer put out by their local grocery store. Unfortunately, I find I spend more money that way than I would otherwise!
While I do keep an eye on the flyer for good deals, the deals often aren't that great. I mostly shop from the produce section on my weekly trips. Meat, staples, and canned goods I by occasionally, as they keep well (meat in the freezer, obviously), so there is no need for them on a weekly basis. Dairy products I buy as needed--not every week. I keep prepackaged foods to a minimum, not only because they are expensive relative to unprepared ingredients, but because they are usually less healthy and take up a lot of counter and pantry space I don't have. Sale flyers do serve me well for most of these items, but I usually buy them on a monthly basis at most.
With produce, the items that go on sale are often still more expensive than other items, so unless there is something I really want to make in the next week, I leave it alone.
When there are no good deals on produce sales I default to salad materials. A head of rommaine lettuce and a few other things (tomatoes if they're in season, oranges if not, cucumbers, etc.) to flesh it out. With only two people in the house eating solid food, that lasts most of the week. I can supplement that with roasted onions or carrots, and stirfry (onions, carrots, cabbage, and celery) as those are pretty inexpensive on a regular basis.
Moral of the story: Always check the sale prices against the regular prices of other items you'd be willing to eat. By doing this, I can feed the two of us on as little as $15/week in the winter.