Usual buy for me is a 3kg pack of basa fillets, 3kg of mince, 2.5kg lamb loin and 2.5kg rump steak. Which will usually last us about 2.5 Weeks.
On occasion well pick up the preseason end roast beef from aldi or a pork shoulder.
A good rule of thumb I've found is to try and get the thickest cut...