My go to cheap dinner is Breakfast for dinner. Omletes and Bacon/Sausage or Pancakes and Bacon/Sausage.
Yes…breakfast for dinner! We do this often. I love to make a frittata for dinner. You can add any combination of veggies, meats and or cheese (I love sausage, roasted red peppers, tomatoes and goat cheese). I like to serve it with a side of fruit or hash browns. Also, I make homemade waffles, french toast and pancakes and all are cheap, cheap, cheap.
Stuffed baked potatoes make a fairly cheap meal, and you can stuff them with lots of different toppings like ham, cheese and broccoli; chili and cheese; or even top with Philly cheesesteak or pizza ingredients.
We like grilled cheese with tomato soup once in awhile. Actually most sandwich/soup combos are fairly inexpensive.
How about making a batch of homemade meatballs (when ground beef or ground turkey is on sale) and freezing them? You can drop them into spaghetti sauce, or make meatballs subs.
We also love souped up baked beans. I caramelize chopped onions, add canned baked beans, cooked ground hamburger (or diced ham or even sliced hot dogs), ketchup, brown sugar, BBQ sauce, and worcestershire. I then throw it into a casserole dish and bake at 350 until it is bubbly.
Finally, we LOVE lemon basil pasta. I really don't have a recipe. I just cook spaghetti noodles and add olive oil, lemon juice and zest, fresh basil, parmesan cheese, salt, pepper and red chili flakes. Man, I could live on that stuff.