Spider-Man Comic Books
Spider-Man first appeared in the anthology comic book Amazing Fantasy #15 in August 1962. If you manage to get your hands on a copy, you'll strike some serious gold. One copy recently sold for just under $48,000 on eBay while the original issue was sold in a 2011 auction for—drum roll please—$1.1 million. Someone's Spidey-senses must have been tingling.
Pokemon for Game Boy
Long before Pokemon Go!, 1998 and 1999 saw the release of Pokemon games for Game Boy. If you happen to be an avid Pokemon collector with an unopened special Pikachu edition of the first generation game, you can list it for $2,999—or, if you have a couple of old game cartridges lying around the house, it's worth a shot to list them on eBay. Recently, a collection of 23 broken game cartridges sold for $150 on the auction site.