According to the memorabilia experts at Professional Sports Authenticator, a Willie Mays autograph is worth anywhere from $50 to upwards of $700 as of 2014. The selling price is subjective and ultimately depends on the condition of the item, its rarity and whether the autograph has been certified as authentic.
Player cards and photos range from $50 to $80. Autographed balls of the Hall of Fame slugger are valued at about $125, and a signed bat fetches around $250. Signed letters and other documents may be worth of up to $600 or $700. As of 2014, autographed jerseys of the former Giant outfielder are currently sold by Steiner Sports for just over $700.