We used to do a monthly shop. I'd meal plan all our dinners, and make sure i purchased all the ingredients needed to make them. I'd also buy all our snack type foods and breakfast stuff in the same shop. We got our meat all in bulk too (lucky enough to buy good bread at the butcher in bulk too) and froze it into meal portions so it was quick and easy. The only things i bought daily/weekly were fresh fruit, vegies, milk and lunch meats. It was very economical for us. Took a little bit of organisation and preparation, but very worthwhile. It was good not having to think of what to cook for dinner every night too, as it was all planned out and all the neccessary ingredients were there.
I think i need to get organised again