A Mickey Mantle single signed baseball is worth about $400-$600. The price will vary based on condition, and type of authenticity that accompanies the signature. Rare examples of a pristine signature or inscriptions like "The Mick" "HOF 1974" or 536 HR's" could raise the price to approximately $1,000. Personal inscriptions like "Good luck Mike" could sell for less than $400. A rarely signed full-name signature "Mickey Charles Mantle" will break the $2,000 price mark as it did in a May 5, 2007, live eBay auction, when it sold for $2,390.
Along with condition, the type of authenticity that accompanies the signature will dictate the price. Mickey Mantle was under contract with the Upper-Deck company before he passed away. Baseballs that have the Upper-Deck hologram could sell in the $1,000-$1,500 price range. And signatures that have not been authenticated could sell at half the market value or less.
In about a dozen recent auctions (June-August 2009) a Mickey Mantle-signed baseball sold for a high of $597.50. The average selling price was about $475. One baseball (inscribed "No. 7") sold for $836.50.
And in an April 2009 auction, a Mickey Mantle-signed baseball (inscribed "MVP '56 '57 '62") sold for $1,792.50! In addition, a rare Mickey Charles Mantle- signed baseball sold for $1,314.50. So it's worth up to over $1000.