I would never pay that much for an autograph. I have only paid for moss's and portis's autographs. They weren't expensive. I got them both for $20 and it came with 5 other big name players too.
If anyone is interested in the thing I talked about above here is the website for it.
http://www.propowerfootball.com/nfl_players.shtml That is a link to all the players but you can click home and see the front page.