I have checked the prices at the huge Asian market on Burnamthorpe. I don't feed raw, so I really haven't found anything cheaper than Costco for the meat I need. I haven't noticed boxes of ground beef in the frozen section but will look when I'm there this week.
I don't find cooking for them difficult or too time consuming anymore, you will get used to it. I generally shape the burger patties and cook them on the weekend and freeze them for use during the week. The chicken thighs get cooked in batches of 12 at a time a couple of times a week and the eye of round roast gets done usually Sunday or Monday and kept in the fridge for their meals during the week. I've been doing it for so long now, it's just part of my life now, ha, ha.