Lazvon
Adventurer
Man, you're very generous! (Otherwise you are a collector... And this is not a positive thing! :-D )
I would pay whatever for a great book (or a unique one) that I really wanted. But on the day to day, the prices I posted are what seems the max reasonable. Not exactly a collector, just someone who is at a very different point in life than I was 40-years ago when I started role playing.
I’ve paid around $1100 (well… £600 or something IIRC) several years back, over the phone, to a charity auction in Cambridge, for a one of a kind signed HARP SF final draft manuscript. I would have went to $2000 for that particular item. Actual retail HARP SF though… probably $50 is my max.