Resale Value: $50 - $1,500

Apart from Super Mario Bros., Pokémon is likely to be the game that most casual gamers played in the past. Of course, with so many versions it's possible that the original U.S. releases are not the ones you've played. Pokémon: Red Version and Blue Version (what was known as Green Version in Japan) sold an estimated 9.5 million copies in the United States. If you're planning to resell just the game cartridge, you'll likely get around the $50 retail value. If you have the games opened but "complete in box" (CIB), those can be worth anywhere in the $100-$400 range, depending on the condition of the box and manual. Sealed versions are where the money's at, though. The limited Red Version with a player's manual (pictured) netted over $1,200 on eBay. A graded Blue Version with a Video Game Authority grading of 85 garnered a $1,500 sale price.