Beef
The two least expensive cuts of beef are usually ground beef and chuck roast. Those are the ones I use the most. I also have canned beef on my shelf, and I have had canned corned beef as well. Canned corned beef is expensive (around $4 a can) but I have found it before at the 99 cents store. Canned beef is more like a roast or stew meat, and in an emergency situation can be eaten cold right out of the can.
When ground beef is on sale, buy a good amount, cook it up with dried onion and granulated garlic, and after draining, out it into freezer bags. Then, when you want tacos, spaghetti, or beef stroganoff, you can just pull out a bag and throw some pre-cooked meat into it. It saves a lot of time.
Watch for the lowest sales of chuck roast. Most often this is on sale during the winter months. Put it in a freezer bag and pull it out when you need it.