Action Comics No. 1, one of about 100 copies known to exist, sold in a private sale for $1 million on Monday. The 1938 comic book is in better condition than any of the others, which explains the high price.  Other copies of this comic book, which introduced Superman and originally cost 10 cents, are reported to be worth over $400,000. The sale was handled by ComicConnect.com, an auction site.