I'm slowly working to build a collection for a future entertainment room in my home.  I've decided to begin searching for some from my favorite childhood movies, starting with Michael J. Fox from Back to the Future.  Surprisingly, every autograph I've come across that's PSA certified is well in excess of $100.  I just recently purchased a PSA-certified Slash (from Guns N' Roses and Velvet Revolver) autograph for $60, so this is surprising.  You would think that since Fox has been around so long and has authored three books that his autograph would be pretty easy to obtain around the $50-75 range.  Is it simple supply and demand or does he not sign very often due to the motor challenges of his Parkinson's disease? I'm ideally looking for a PSA-certified signed photo of him from Back to the Future, or just a photo of him from that period in general.