Rob -
I just looked at the bill for the work the machine shop did for me. The labor for cleaning and boring the block, tearing down and checking the head (it had been rebuilt already, but sat for a while) was $80. Of course, this varies with location, amount of work involved, etc., but will give you an idea for the labor.
As I said, my head had been rebuilt and was in pretty good shape. If it hadn't, I would have bought new valves and springs for it. It's just not worth skipping over, and they're not that expensive. The shop did resurface the head, and installed new stem seals. Hope this helps.
Mickey