You can get a rebuild kit for around 80 bucks and at any shop that sells Holly carbs you can buy a new automatic choke assembly $???. Rebuildg a Holly is no problem, the only thing you want to watch is in the replacement of the Idle speed valves, read the instructions carefully.
All that said, give him 50 - 75 bucks. A 4bbl Holly at Auto Zone for 175? Does that include the throttle body for the vehicle it is going to be installed on? If so, WOW.
Most Holly carbs I have seen rebuilt or new that include the throttle body run in the $200 - $350 range.
:-"
Good luck!