How much would a davy jones of the monkees autograph be worth?

What is on the postcard? Is there a picture of him? That makes a big difference for Monkees/Davy Jones collectors. The problem with the age of yours is that there is tons of stuff floating around from the 80s. Unless the card is something very unusual (rare picture or mentions something more personal), or you get lucky enough to have inexperienced bidders, it probably won't fetch more than your opening bid. If that's more than $2-3 you won't even get that. Davy has always been more than generous with his autographs which makes it "worth" very little. Except to a lifelong fan like me! :-)