How do I value sports memorabilia if it might be one of a kind?

I have an EA Sports NHL 96 video game (Sega Genesis) autographed by ten players of the former Winnipeg Jets team. The last year they played as the Jets in the NHL. Some of the signatures I have are Kris King, Nickolai Khabibulin, Alexei Zhamnov and Shane Doan (rookie year). I am the original owner and as far as I know there is nothing like that out there. How do I value something like this? I'm not sure I want to sell it but I just want to get an idea of its monetary value. Any ideas?