What are some of the rarest and most valuable 1980s comic book issues, and where can one find information about their value?

Some of the rarest include *Amazing Fantasy #15*, *Superman #200*, *The Dark Knight Returns*, and early issues of titles like *X-Men* and *Wolverine*. Their values can range from tens of thousands to hundreds of thousands of dollars. Information about their value can be found on comic book price guides (like the CGC or PGX guides), auction records (like those from Heritage Auctions or ComicBookXchange), and specialized comic book forums and websites.