The comic book that sold for the most money is
Action Comics #1 (1938), featuring the first appearance of Superman. In 2021, a CGC graded 9.0 copy sold for
$3.25 million, making it the most expensive comic book ever sold.
It's worth noting that there have been other high-priced sales of Action Comics #1, and the record is constantly being broken as the market for vintage comics fluctuates.