The problem is I typically only want a single burger, but I have to buy the ingredients for four or more. To purchase all the ingredients to make a home made quarter pounder with cheese, I am spending around 40-50 USD. Sure, I could make five or six with those ingredients, but that is irrelevant if I only want one. And many of those ingredients are perishable. Unless I am eating several quarter pounders a week, I am saving money by getting a quarter pounder from Macca's when the mood strikes.