What is the value of a 1955 sandy koufax game-used baseball?

Answer 1

If the Baseball is signed by Sandy Koufax on a clean white baseball it is worth between $250.-$400. Value is based on average prices of recently closed auctions. Prices may vary based on condition, and the type of authenticity that accompanies the baseball. Signatures that have not been properly authenticated could sell at half the market value or less If the baseball is signed and is "game used" it will have a lower value based on condition. Without being able to prove it was game used by Sandy Kofuax you cannot sell it as such. Any added value will rely on your ability to prove so. Nothing short than a letter of provenance from a team official or player would be good enough. A letter from a fan at the game will not hold much weight if any. Ig the baseball is not signed, it would have the value of a vintage baseball in used condition.