stews and casseroles - use cheaper cuts of meat (not cheap and nasty meat, just cuts which are cheaper because they need slower cooking)
Chicken - buy a good quality chicken and then use every last scrap of it. There are five of us and we get 4-6 meals from one chicken.
Jacket potatoes with fillings. Risotto - if made with simple, quality ingredients it doesn't cost much but tastes gorgeous.
Things on toast (egg, beans, cheese) can make a main meal - add a bit of salad on the side to bulk out the veggies, I often put a big dish of cherry tomatoes out.
Home-made pizza - easy, cheap and tasty.
Eggs - omelette, scrambled egg, souffle etc can form the basis of many meals.
All the usual minced meat recipes.
Home-made soup - again, quick and dead easy. Serve with a good carb, home-made bread, garlic bread, savoury scones, crackers, whatever.
Pastry - if you can make a bit of pastry there are umpteen pies, quiches, flans etc you can make using any odd things in your fridge or cupboard!
Pulses - these are incredibly cheap, especially the dried ones. You can make so many meals, try Rose Elliot's 'The Bean Book' for ideas. Her 'Cheap and Easy' is also great for general cheap veggie meals for families.
And on the subject of veggie meals, eat meat-free meals 2-3 times a week, that really helps keep costs down and is good for you too!