How much is a Tom Brady autograph worth?

I got injured overseas and tom brady sent Autographed Foot over to the new england guys who got hurt. Its 3/4 white and 1/4 brown from superbowl 39 and says limited 10,000 im never going to sell it but i have been curious on how much it is worth. it also came with a certificate of authenticity from the NFL. anyone have any idea on how much it would be worth?