other than eBay, can you provide other places to determine what market is for specific coins/sets? Roy, I think you provided something previously, but I lost the information...
You can check any of the auction sites - Heritage, TeleTrade, Yahoo, Amazon etc. And you can check realized auction prices at any of the major auction houses like Superior, Bowers & Marena, American Numimsmatic Rarities, Goldberg, Steinbergs etc. Just do a Google search for any of those names