Make a pot of whole wheat pasta (spaghetti, rotini, etc) & make 2x the normal amount of noodles, and set half aside. For tonight, Add meatballs or browned beef and sauce.
With the other half of the noodles, throw it and some meat of your choice (chopped ham, browned beef, leftover turkey or chicken, pepperoni, etc.), mix in tomato sauce & spices (we usually use pasta sauce or tomato sauce & Italian spices [basil, oregano, thyme, garlic]). Optional: add a small container of lowfat, small curd cottage cheese. Throw into a freezeable casserole dish and freeze. To eat, throw some cheese on top (1 to 2 cups) and/or seasoned bread crumbs. Cover and place in an unheated oven. Turn oven to 350 and let cook for 30-45 minutes, or until bubbly.
We make a lot of veggie burritos. We buy the pepper & onion veggie mix for stir fries (in the freezer section of Kroger, on sale for $1 frequently). Cook 1 to 1 1/2 cups brown rice (we use instant brown rice in a pinch) until done. Set aside. Saute pepper & onions with garlic until desired doneness (we like our onions translucent, but still a little crisp). Add a can (15oz) or 1 to 1 1/2 cups of black beans (it's cheaper to buy in bulk & cook & freeze in 1 to 2 cup portions). Add a can of diced tomatoes (sometimes we cook the tomatoes & rice together & use the tomato juice as part of the rice cooking liquid). Mix all together, and sprinkle with taco seasoning to desired amount (we use 2 T, approx). Serve in burrito or taco shells with plain yogurt (in place of sour cream) and salsa and cheese. Leftovers can be made into a Mexican casserole and baked similarly to the above baked pasta.
We buy in bulk. If you don't have access to or don't want to get a membership in Costco or Sam's Club or BJ's Wholesale Club, try GFS (Gordon Food Services), which has no membership fee but sells bulk food items (they only sell food/foodservice stuff, no other misc. items like Sam's/Costco/BJ's). This is where we buy our pizza sauce ($3 for a giant can, which I split up & freeze in normal pizza size portions), whole wheat pasta, pizza shells, sliced & shredded cheese (both freeze well), etc.
Also, check out the local ethnic grocery stores: You can often buy beans, rice, and other other items cheaper here. The local Somali grocer has 4# bags of black beans for $5, and it cups up to about 16 cups, which is a huge savings over the cans of beans. You can cook them in a crockpot, too, which is super easy. Also, the ethnic groceries, especially Indian, has "ready meals" which are sauce packets to go over rice for $1 or $1.50 each, and these are fun to eat as something different; we use 2 sauce packets for 4 people, over 4 to 6 cups cooked rice.