I don't know how it compares cost wise. It all depends on what you buy. I buy from a local source that is somewhat cheaper than when I bought in a store.
It comes frozen and must be kept frozen. I buy in 2 lb chubs. I open one chub and when it is halfway gone, I take another out of the freezer. I have two 15-17 lb dachshunds so you'll have to adjust for the size and activity level of your dog. If you have a natural pets store in your area (like Natural Paws) they can help you with that.