ComicLink Sold an X-Men #1 CGC 9.6 for $350,000
Food for thought… doubling this result to get a rough estimate at the value of a 9.8 puts X-Men #1 CGC 9.8 in the range of The Hulk #1 CGC 9.4 and the three Amazing Fantasy #15 9.6s for the title of most valuable Silver Age book. I'm not entirely sold on that, to be honest, but it's always fun to speculate.