While this card only averages in at 4.00 including shipping on Ebay I always like to look at the highest amount gotten from the "Sold" section to see what the cards were and how much they went for. I also like to look and see what the most expensive card available right now is. Many times you'll find sellers at the top of the spectrum asking insane prices for their cards. The highest one isn't too terribly out of whack although it comes in much higher than any sold cards of his in the last few months.
Here's the link to the auction = Shawn-Williams-Rookie-Autograph-Bengals
As I said, I don't think it's a terrible price considering that it's numbered to 10 and it's autographed. I personally wouldn't spend that much but you might have a die hard Bengals fan or a set collector that needs this particular card. All it takes is one person out of millions of collectors to pull the trigger. If it's one thing I've learned from the Beckett boards, every player has their collectors and what you might discount or think is not that important in your box breaks or lot purchases might be very important to someone else. Hang on to those singles cause you just never know!