That would work locally. I'd imagine there'd be a huge variation in ingredient cost worldwide, or even between the saturated Denver market for homebrew supplies and, say Durango where Denver may be the closest shop. You'd have to add in your own costs and again, how? Are you buying grain by the pound, ounce, bag? How about hops where I can get a pound of Magnum for the cost of 4 ounces, repackaged? My take on the request is there would be too many variables to track on a site like Brewer's Friend; however, a simple spreadsheet at home could do the trick.