What is value of a team signed 1978 Yankee baseball good condition?

1978 New York Yankees Team Signed Baseball

A 1978 New York Yankees Team Signed Baseball with the key signatures: Munson, Nettles, Piniella, Lyle, Martin, Hunter, Guidry, Jackson, Gossage, and Lemon is worth about $650.-$850.

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. Prices may also vary based on the amount of signatures, and key signatures acquired. The more complete the baseball with key signatures the more valuable.

If the signatures are not properly authenticated the baseball could sell at half the market value or less.