Out of thousands of Charizard cards from this era, only about 121 are considered to be in mint condition.

A 1999 Pokemon card of the creature "Charizard" was sold for $420,000 during an auction last week. It's one of 121 such cards to be given a "Mint 10" status, meaning it's in brand-new condition.

Here are eight Pokémon cards that have become absurdly valuable, and why collectors are willing to pay ridiculous amounts for pieces of cardboard.