I don't need to. I follow a pattern of shopping so I do not need to lower my grocery bill as there's only the two of us now, DH and me, then the cat, the dog and a chinchilla. I shop for meat every two weeks, vegetables every week, then pantry items when they run low and buy only what I will need next for my cooking tomorrow or the next day or the day after next. Almost everyday, I go to the internet look for some recipes that will use what I already have from the pantry, freezer and refrigerator. I go from there. There are times I am lazy to cook, so one look in the pantry and I know I have to cook...or not. The thing that actually makes my grocery bill low is how I store my meat and vegetables. I don't use freezer bags. I use my foodsaver and carefully pack a serve for two people and store my meat in the freezer that way. I do my own stocks and freeze them too, use as I need. Ice cube containers are good for those. I have a good breadmaker and I bake my own bread every other day -- almost. Organize...organize...organize...you do not have to buy cheap stuff if you know how to organize your shopping sprees in the supermarket. And there are times, cheap meat cut is the way to go for some recipes, or most recipes. Mince is one good almost-universal way to make a meal go further. and don't forget coupons when going out shopping. I cut mine each week from the local newspaper and organize them as a group like dog food, soup, bath products, etc., in empty-used-to-be letter envelopes that comes in the mail. The extra used-to-be-envelopes also serves a my shopping list.
'Hope this helps. I do not have to economize. It is a habit I taught myself years ago when I was almost starving for not learning how to cook in the first place. I was single then. After 1 daughter and 3 always starving boys on their own now, it had been a long road of learning and maintaining a habit.
Do not stop learning everyday.