Meal planning and meal prepping! It saved us when I was out of work and we went down to one income. I got out of the habit for a while, but now I'm back into in preparation for baby #3 coming this summer. We're currently 2 adults and 2 kids (6 and 4).
Every 8 months or so we buy 1/4 cow from a local ranch. It's approximately $500 up front, but then we don't buy beef for 8 months. There's no doubt at all in my mind we save a ton of money there.
I spend 1 day every other week making a 2 week meal plan. I usually do a
Walmart grocery pick up order so I don't even need to go into the store and it helps me keep track of what I'm buying and how much I'm spending.
The next day is prep day. I wash and cut all fruits and veggies, cook up or separate any meat that needs it, and then I start to assemble. I make burritos for the freezer (breakfast and bean/beef/cheese), breakfast sammiches, lasagna and stuffed shells, separate chicken to marinate and then grill, 3lbs of seasoned chicken and taco seasoned chicken in the crock pot, spaghetti sauce to portion into several meals, sloppy Joe's, etc.
2 days of planning and cooking/cleaning and most of our meals are ready to go for the next two weeks! We're also simple lunch people: sammiches, soups, salads, leftovers, etc.