My instinct says don't sell it. I for one wouldn't, not if I had gone through all that to meet Biehn, (Whom I have met, and gotten an auto of, but not of my Hicks figure...arrrgh!), so I would not sell it.
Plus, if it is worth $500 NOW, to someone, in time, it will be worth even more.
The figure is so rare now, that the prices are what you see. Note the Toys McCoy Indys, rare. One day, Hicks will draw even larger prices. If you have a pic of him signing your Hicks box, hang on to that, and put it with the figure. Frame it. Save it. And one day, we're talking over $1000. Easy. But not for a while.
If you sold it to me for $500 (Or anyone else..) that is what I would do with it. Wait and sell it for twice. You did the work, you should get any top collector dollar if you do ever sell it.
But, I wouldn't anyway.
Ever. But, that's just me.
BTW, I paid around $250 to get my Hicks and that was a LONG time back. Late 2006. So...it will only go up. Hang on to him!