Three cheap chicken meals. Buy 2 x 1kg packs of chicken thighs (skin and bone on).
Day 1 - roast one pack of the chicken, and have a roast dinner with stuffing (the cheapest - bulky and filling), roast potatoes, carrots, broccoli. 3 thighs for DH, 2 for you and 1 for toddler.
Day 2 - roast 2nd pack, and strip every last shred of meat off the bones. Divide it in two. Use half to make chicken noodle stir-fry with a 2/3 of a large stir-fry veg packet. Make stock with the bones, or freeze them until you have more.
Day 3 - using remaining chicken. Cook a load of rice and cool it. Make chicken fried rice with the rest of the stir-fry veg packet and a couple of eggs.
Other cheap meal options:
Buy a packet of Aldi cheap frankfurters (fridge) for aroubd £1.20, and make a pasta sauce with an onion, garlic, tinned toms, slice up the sausages and put them in. Serve with pasta. You can also add mushrooms and smoked paprika if you have it.
Do the same with cheap bacon.
Make chilli/bolognese go further by adding oats to bulk it out.
Three bean chilli is a protein rich cheap option. Buy three tins of any beans in the supermarket. I tend to use chickpeas, red kidney beans and butter beans. Fry a chopped onion until golden, add a diced red pepper (frozen also fine), garlic, two tins of tomatoes, chilli powder (or make your own blend), and the beans and simmer. Serve with rice for bulk.