Yep-- when I was feeding all kibble, my very active two 45lb pit bulls and my lazy 65lb lab all ate the same amount-- 2 cups a day of Taste of the Wild (1 in the AM, 1 in the PM).
If you're getting Dog Chow at 50lbs for $20, then you're paying 40¢/lb, and feeding 4 cups per day. If you feed a food that you only need to feed half that amount (and bear in mind that what the bag says is the right amount is almost always too much-- they're trying to sell food, remember!!), then you could pay roughly twice as much on the food and come out the same, cost-wise--
so 40¢/lb at 4cups per day is equal to 80¢/lb at 2cups per day.
Does that make sense? I actually do a much more detailed cost analysis when I'm working this stuff out, but this will give you a rough idea of the cost/cost savings.
A couple of brands comparable to Kirklands (actually made by the same company) are Diamond Naturals and 4Health. 4Health Chicken and Rice is about $30 for a 35lb bag, which is 85¢/lb. Diamond Naturals Chicken and Rice is about $29 for a 40lb bag, which is 72¢/lb-- making it even cheaper than dog chow since you only need to feed half as much. Canidae is another one that's similar, and that you can often find for around $1/lb. PLUS, if your dogs are healthier, that's less money spent on vet bills.
Those three brands can usually be found at local pet supply stores, but I usually shop at Tractor Supply, Atwoods, other farm and ranch stores, or farmer's co-ops for the best prices.