There is a way I feed 6, 2 adults and my 4 dc are under 7.
Porridge with jam for breakfast and toast with peanut butter
Secret to main meals is basing a all your dishes around a few basic ingredients.
Potatoes, rice, lentils a couple of varieties, chickpeas, kidney beans, dried sultanas, dried soya mince, pasata, coconut milk, fish sauce, beetroot, carrots, spinach, mushrooms, onions, garam masala, mixed herbs, tomato sauce, stock cubes, red wine, oil, paneer, cheddar, cocoa powder, sugar, icing sugar, flour, eggs, salt, pepper, butter, milk, bread, apples, bananas and clementines.
From this you can make rice and potato soup, beetroot bourginon, tac a tan, spinach paneer curry, chickpea curry, woolton pie, lentil soup, beetroot and spinach pilaf, fruity mince, lentil bake on jacket potatoes, faux meatloaf, cheese and onion spanish omelette, mushrooms and lentils on toast, carrot soup with bean dip on toast. Plus puddings, bread pudding, beetroot and banana cake, chickpea chocolate brownies, chocolate, coconut, peanut porridge squares, baked bananas with a peanut chocolate sauce, chocolate custard and clementines, baked apples, jam sponge, banana and sultana bread, flong flong, sultana biscuits, jam tarts and then there's fruit for snack.
Sure I get more out but I can't think of more. You just have to buy enough quantities of few ingredients. This would be cheaper if you had some store cupboard ingredients and fancier if you had a few extra pennies.