We've spoken about Beanie Babies and Barbies so far, which would stereotypically be seen as girls' toys, but don't worry gentlemen. The toys which you still have hidden away and told everyone else you threw out years ago have hidden values of their own. In fact, the most macho of all boys' toys - Mattel's popular 'He-Man' range - are some of the most valuable of all.
The action figures themselves aren't the most valuable aspect of the toy range; it's the playset which collectors are most interested in. For some reason, many people bought the figures but comparatively through bought the full-sized 'Eternia' playset which gave the figures an environment to play on. Perhaps it was overpriced when it was released, or maybe it just wasn't very good? Either way, it's rare now, and rare is valuable. To be precise, it's $10,000 worth of valuable.