I have been doing the same if I find a whole chicken on sale, cat food has gone from 53 cents a can to 83 cents a can my cat LOVES chicken and right now fresh chicken is cheaper than cat food!!!
You're lucky. My cat won't eat human food. He's addicted to Fancy Feast which makes me wonder what's in it. Stuff is expensive. I have tried slowly mixing in real food into his canned food but he's just too smart.
I cook for my dog so at least that saves me some money... except when dog steals cat food...