So I have pic related, but it's signed by Dan Jurgens, Brett

Ebay is probably the easiest way to ballpark, but I wouldn't expect it to be worth much anyway. Too popular of a story.

>>94722994
you can get it officialy graded or appraised for a small fee
the most important factor in determining value is the condition of the book, aside from that it is a popular book so there is reasonable demand, but those aren't very sought after signatures, they'll increase the value, but not very significantly

>>94723201
Yea I'm thinking of getting it graded soon. Going through my old collection and seeing what would be worth sending in atm.

Being the TBP, I don't know that it would be worth much at all.
Then again, I don't think that the issue would be worth anything even with the sigs.

>>94722994
Easy, just check Wizard magazine.