Also,
I know that a number of NET54 collectors who would trade/sell T206s live in the NYC/NJ area. You may find them able to give you better deals / better trades than your local card store. And you might find that they are willing to buy duplicates that you don't want as well.
Shameless plug....I am one of them
Best,
Scott
scottglevy@yahoo.com
Added to say that by far the most comprehensive pricing list is VCP (vintage card pricing) which is a subscription based online site. Other reasonable (cheaper) alternatives are the PSA SMR guide, and t206.net and just good old fashioned ebay watching.