Since he was introduced in 1963, Iron Man has become a top tier character in Marvel Comics, leading dangerous missions and outfitting teams for battles with the galaxy’s worst foes. His ingenuity and amazing technology have made him an incredible superhero, while his cocky attitude and boatloads of confidence make him an interesting character.

When Iron Man debuted in Tales of Suspense #39 the book retailed for just 12¢. Seven years later when The Overstreet Comic Book Price Guide #1 was published in 1970, Robert M. Overstreet priced a Near Mint copy for $6. By the Guide’s 10th anniversary, the book had jumped significantly to $210.

When the Guide #20 was published in 1990, Tony Stark’s first appearance was valued at $875. It took another big leap in the 30th Guide, landing at $4,200. In 2007, nearly a year before Iron Man kicked off the Marvel Cinematic Universe, the book reached $10,500.

Just three years later for Guide #40, Tales of Suspense #39 nearly doubled to $20,000. In the Guide’s recently released 50th edition, a Near Mint copy of Iron Man’s debut is valued at $56,000.