Hi Waz,
For T206 here on LI, the few card/collectible shops have exorbitant prices. You would do better at ebay and auction houses., but more so with private transactions. Antique stores, if they have any, which is rare, it's the same thing. Outside of T206 it's better to pound the pavement and look for obscure cabinets and postcards, etc., but even that is picked pretty clean
Paul