With turkey calls, what they are worth is only what they sell for. Best way to get a good value estimate is to watch ebay. Type in "turkey call", click on the first call that comes up, then click on the catergory, "turkey calls". Once you get to that group of listings, around 37-40 pages, type, "Ben Lee" into the search block. Then save that search. Anytime someone lists a Ben Lee call you will be emailed. Watch the auctions and you will get a rough estimate.
Second method is to take really good pictures of the call that show all sides, inside and out, up close, every word, the autograph, everything. Especially any cracks or flaws on the calls. Post them on ebay with a starting bid of $0.99 and set the reserve at something very high like $1,000.00. This way you can see what collectors are willing to spend on the call, not end up having to sell it, and only have to pay a listing fee of a few dollars to obtain this information.
"Instruments of Mass Destruction"