The authenticity of Musk's signature has been verified and is accompanied by a certificate of authenticity from JSA. Bidding for the photo starts at $25, with estimates ranging from $100 to $200.

While it's unknown if he's ever been compensated for his autograph, there are more than 2,000 Jameis Winston-signed items on the James Spence Authentication website. Melina Vastola/USA TODAY Sports ...

He started buying up dated Ali signed items and strung them together on a website to show Ali's autograph from the 1960 through 2003. Over time, he became an expert in Ali signatures.

A third generation Ford dealer in Las Vegas bought the first and only baseball signed by Henry Ford that has passed authentication for $15,038. "They already think I'm nuts anyway!," he said.