The most valuable celebrity autographs just happen to be on pieces of memorabilia. For example, a 1963 Gibson ED-1275 guitar that belonged to Jimmy Page of Led Zeppelin was auctioned for $73,000. Sometime during their brief marriage, Joe DiMaggio and Marilyn Monroe signed a baseball. It's allegedly the only item that's ever has been signed by both DiMaggio and Monroe, selling at an auction in 2006 for a whopping $191,000. The 1965 contract of guitar legend Jimi Hendrix, signed by him only five years before his untimely death, sold at an auction for $200,000 in 2009.