A copy of Iron Man #55 CGC 9.8 white pages has just sold for $9000 at comic book consignment and auction site Comiclink, a record for this issue by a significant margin. This 1973 Marvel comic plotted by Jim Starlin, scripted by Starlin and Mike Friedrich, and penciled by Starlin is the first appearance of Thanos and Drax the Destroyer. There are 40 copies in CGC 9.8 and none higher.
At this level, the comic appears to be joining a very small group of Bronze Age Marvels that can approach the $10k range in 9.8, including Incredible Hulk #181 (first Wolverine) and X-Men #94 (All-new, all-different team begins in series after first appearing in Giant Size X-Men #1).
Though Iron Man #55 has been considered an important Marvel key for quite some time, it's been a particularly good year for both Thanos and Drax — Thanos appears to be looming large over both the comic and cinematic universes, while Drax is part of a major franchise himself in Guardians of the Galaxy — and when we flagged this comic as one to watch in the Vintage Paper column of Bleeding Cool Magazine #1 last year, we noted that copies in 9.8 could be had in the $3000-3500 range at that time.