Cheap:
Jacket potatoes with leftover chilli that I have in the freezer
Puff pastry pizza - roll out a sheet of pre made pastry, score a line around the edge, brush with milk or egg, bung in the oven for 10 minutes, take it out add pizza sauce / tom puree whatever you like and then whatever else you have in the fridge as a topping. My kids love salami olive and cheese
Quick:
Mac and cheese, this will be a ready meal as a rare treat because it so unhealthy but my own version never tastes as good as M&S...
Chicken quesedillas - my online shop delivered me four ready cooked chicken breasts instead of six. Will turn the spares into quesedillas with sour cream, cheese, tinned corn, sweetcorn and chilli
Linguine with chorizo, red onion, pine nuts, tenderstem brocolli. Put water on to boil, finely slice red onion and fry off with a splash of red wine vinegar, add chorizo once started to caramelise, add linguini to the water, toast the pinenuts in a dry pan, add the tenderstem two minutes before the pasta is cooked. Drain the pasta and tenderstem, lift the linguine and brocolli into the onion and chorizo pan with a big spoonful of the pasta water, add the pine nuts and liberal squeezes of lemon juice. All done in ten minutes.