How much is this basketball worth signed by NBA Hall Of Famer David Thompson?

I have a basketball signed by David Thompson, an NBA player in the hall of fame. How much is this worth?How much is this basketball worth signed by NBA Hall Of Famer David Thompson?
I guess that would depend on if your can authenticate it or not. Do you have a notarized letter of authenticity, or a picture of him while signing the ball? You must first be able to prove the David Thompson is actually the one that signed the ball. With that in hand you could take it to various Sports memorabilia dealers and get their oppinions. Get five letters of opinion, throw out the highest and lowest and take an average of the remaining three values. That should be close. Memorabilia is only worth what a buyer is willing to pay. There is really no set figure like a Kelly Blue Book, or Home Appraisal.How much is this basketball worth signed by NBA Hall Of Famer David Thompson?
send it to me ill get it appraise for you