I can see how that would stack up with 3 nearly adults in the house, but I think with some careful planning you'd be able to bring it down.
Loosely, I base our meal plan on a pasta / gnocchi, mince, chicken, fish, rice / veggie, sausage & Sunday Dinner. We eat very little red meat really (tend to use turkey mince and some pork - beef very occasionally, usually a slow cooked cheaper brisket cut).
So I'd try save a bit of chicken / gammon from Sunday dinner to put in a pasta bake on Monday for example (bulked out with veggies served with garlic bread & salad). I use pulses a lot to bulk out dishes, especially mince. I've got an 11 & 7 year old so can split a 500g pack in 2 and add lentils, carrot, celery, onion, courgette, peppers (if making chilli) and make a bolognese and shepherds pie - one will go in the freezer for the following week (you might be able to this with a bigger pack of mince).
Chickpeas & veggies make great cheap curry's, or try veggie lasagna - much cheaper than buying meat. And try subbing some of the meat out for more veg in recipes that won't miss it e.g joe wicks gnocchi bake with chicken, kale & mushrooms - I can put one chicken breast in that for us and it usually leaves a portion for someone's lunch the next day.
We also aim to have one really cheap meal a week, like egg & chips / jacket potato & beans / lentil & bacon soup w/ bread / pesto pasta / omelette / beans on toast. And freeze your leftovers if not being eaten the next day. We regularly have a freezer raid and all end up with a random, home cooked, microwave meal each.
If you plan out your week you can make sure any left overs (bits of veg etc) can be thrown into the following days meal and you don't have waste. Only buy what's on the list (don't forget lunches / treats) and keep a loaf of bread & litre of milk in freezer to limit last minute shops that always cost more than planned. Freeze chicken breasts / thighs separately/ sausages in pairs if your not using straight away so your not forced to defrost / cook more than you need too.
Pinterest is great for recipe ideas too, especially vegan / veggie if that's not something you cook a lot.