I bought my used head on eBay for $150. I got lucky, it was fine.
I spent $650 at the machine shop for a complete rebuild with new seats, valves, guides, valve grinding, resurface (-0.080") and cc of every chamber. That was very fair here in New England.
I asked him if I brought in an engine if he would do it. For the boil out, line bore, cam bearings, rod truing, crank grinding, deck resurface, new freeze plugs and oil galley plugs, etc., I would probably spend another $1,500 to $1,800. That does not include assembly, which is fine, I can do that myself.
So to me, that price is fair, because it does include a warranty.
TRF does rebuilding and I have heard that they do great work, with the Spadafore family now doing the work. They were famous for racing engines when I lived in PA. I just got a reconditioned rocker arm assembly from them that looked better than new for less than the price of the new parts. I would not hesitate to send anything to them, either.