Actually prices or demand, for the Avatar Illustrated have come down. The highest price was 9.8 "privately sold for $300" according to ebay. It last closed at $218. After that, there been two sellers ,who been trying to sell, one selling a 9.8 for $450. A seller that looks to have a raw copy that keeps lowering his or her amount. The seller started with bid $99 with BIN149, then lowered to bid $89 with BIN $109, now $89 with $99. I think buyers realized it was a preview book or the ones that really want this book know where to get it.
As for the Goon #1, supply for 9.8 has dried up, knowing that movie is coming out sellers are holding on to their supply. Accordding to the census, there's only "18". I am sure if someone was smart enough put a 9.8 auction style,not BIN the price would be beat the current record. The reason, Sellers who already own the book would bid. The movie is still about two years away, nothing but potential. Raw copies seem to remain stable 90-110. There's a guy trying to sell a Goon 1 and 2 9.6 for 599. The seller been trying those book nearly a year now. I think that's just a case bad marketing or "look what I have".
Goon 3 has increased in price. According to GPA, Goon 3 9.8 is worth more than Goon 2 9.8. That being it's the first orgin of the Goon.