A 33 lb bag is about $66, or about 12.5 cents/oz. He gets fed 2x day, a total of 2.5 cups per day. Liquid weight would be 20 oz. I'm not sure what the dog food weighs per cup, but will use that as worst case 20 oz. The bag lasts more than a month, so I know the true weight is less than 20 oz per day.
20 oz works out to $2.50 per day, plus the occasional table scrap. The cheap dog food is 6.3 cents per oz. So we spend an extra 6.2 cents per oz/$1.24 per day on him. We don't begrudge that.
That has gotten us a 10 year old buddy who is happy, active (runs and swims), and has no health problems beyond a touch of arthritis in his hips.