I keep 22 goats at the moment, Bamford. As to cost, well, yes, in winter they do put away a fair bit of haylage and goat feed etc. Summer not too bad, they do have hay at night, but fill up on grass and branches during the day. Goats browse more than graze, and eat hawthorn, brambles, wild rose etc. as well as tree branches. Then there is the worming, and any medication etc.
As to prices when selling - pygmy goats are much sought after, and fetch a good price - £150 plus for a kid, male or female. I have sold my sanaan nanny kids for a similar price in the past. Registered dairy breeds, the females can fetch even more. As I have a lot of grass, its probable I will run this years kids on, and sell next summer when they are nearly ready to breed from.
Having said all this - I have people coming in droves giving me goats for nothing. We seem to have turned into a sanctuary. But at least breeding from the free females, I can recoup some feed costs.