I have often seen magazine articles that suggest creating a menu and then buying the items. I find that this doesn't work as well as you might think. You end up buying things that are NOT on sale just to make certain dishes on your menu. It's much better plan your menu around foods that you have on hand. Once you are stocked up you'll find that you usually have the ingredients for many delicious meals in your cupboards and freezer.
Meat is usually the most expensive part of your meal but there are ways to cut down on the amount you use and also alternatives. Look for recipes that use lentils or red beans. Some people recommend TVP (texturized vegetable protein) as a supplement to ground beef. I haven't actually tried this myself but here are a couple of suggestions from people who use it: in "casserole-type" dishes that use ground beef use about 1/4 lb. ground beef and about 1/4 cup of granule TVP. With spaghetti, throw it into the sauce and it hydrates itself. For tacos, hydrate it in about 1/2 cup of water and after the ground beef is cooked add it with the taco seasoning mix. It also works with BBQ sauce for Sloppy Joes and in chili without any ground beef.
Chili can also be made without ground beef or TVP. Just use extra beans. It can also be made with chicken or ground turkey (although the prices of those are not all that much cheaper than the beef!).
Another way to save on meats is by visiting your local grocery store at different times to see when they put the discount meat out. This is the meat that has almost reached it's "sell by" date and it is often drastically reduced in price. Depending on your store it might be labelled with a bright orange "Manager's Special" sticker or have a coupon on it for dollars off. There is NOTHING WRONG with this meat...the meat man most likely just came by 10 minutes ago and took it out of the case to change the label. Our best bargain ever was the day we found corned beefs (which were already on sale at 99 cents a pound) with $3.00 coupons attached to each one. We got several of them for 39 cents each and stored them in the freezer for future use. When you buy the discounted meat either use it right away or immediately freeze it.
Eggs can be used as a protein source instead of meat as well. They are frequently on sale and can be cooked many different ways. You can have a "breakfast supper" with eggs, toast and fruit or a "snack supper" with devilled eggs, raw veggies and dip, etc. Kids, especially, get a kick out of that sort of change of pace!
From Delta Jackson: My children, ages 9 & 13, love a pasta helper product. It has become impossible to feed our family on one box of this I brown 1 1/2 pounds of ground turkey in a small amount of cooking oil, drain off the grease then prepare the rest of the recipe according to package directions adding an extra one cup of milk and an extra 1/2 cup of water. I stir in the sauce mix then throw in about four extra handfuls of macaroni, bow tie pasta, or the twisted pasta to match the pasta used in the box dinner. This allows several more portions for our growing family.