Would he be open to eating quorn? That is sometimes cheaper, I use the asda meat-free range and it really is tasty.
I buy my chicken breast from a local indian supermarket, you get so much more for your money, by the time it is diced you get 3 times what you would in a little asda tray for less the asda price!!
Failing that I buy the 3 for £10 range. pork loin steaks are tasty you usually get 6 in a pack so 1 each means 3 meals. A cooked chicken can make SO many meals- pie, curry, casserole anything like that- it doesnt all have to make a 'sunday dinner'. Mince (less than 5% fat) can work out at being a tad expensive but if youre making a bolognese or chilli you could do 50/50 meat and quorn to bulk it out or just load it with veggies. I also use quite a lot of the cooking bacon pieces, its actually usually nicer for meals as its a little thicker than normal rashers, goes great into soups, beans, omlette, pasta, sandwiches.