a 600 cfm...$35.00, a 650 double pumper $75.00- $100.00, 2 barrel 500 cfm,$40.00, a 3310/780 cfm $50.00

You need to be more specific... There are many different Holly Carbs out there. What's the external condition? What's the CFM. 2BBL, 4BBL. or 3BBL (Yes they made one)?

As much as the interpretation costs for your dismantling of the English language. Depends on the size and application.

Lots are worth $10 each. If it is off a rare car, could be $200.