GOTnewbie

I am new to this forum, which I came across with interest! I have been offered a lettered limited edition ASOFI which includes the MM GOT & ACOK with future rights. No ST GOT/COK. I have done a bit of reseearch and seen some pretty big prices on abebooks but there is not much else listed (ebay, etc). What in your opinion is a reasonable price to pay for this....it is in almost perfect condition! I am a huge fan and think that this will be a real collectors items want to be cautious . Thanks