How much is a 1987 Chicago Cubs autographed baseball worth?

Casey Stengel single signed baseballA Casey Stengel single signed Baseball is worth between $650.- $750.

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. Add for inscriptions.

If the baseball is from the 1972 World Series it could have a lower value based on condition. A clean white baseball would be most preferred to display the signature. Added value as a World Series game ball would be in your ability to prove so. A "Game used" baseball would have to be accompanied with provenance, and the quality of the provenance will dictate the added value. A letter from a player, team, or League official would be acceptable. A letter from a fan at the game would not hold much weight if any. Without provenance the added value will rely on the buyers belief in your story.