Brand name: Chicken
Where to buy it: Grocery store/butcher
How much it costs: 6-7$ (cheaper if it's on sale)
Lasts approximately 1 week per cat = <1$ per day.
Pick up a whole chicken, extra hearts, giblets, and liver. Grind it all up when you get home, add a pinch of salt and an egg yolk or two. Voila, natural, healthy, and very cost efficient.
"Education is a progressive discovery of our own ignorance." -Will Durant