If you or your kids have Pokemon cards sitting in the attic or the basement somewhere, you might want to go take a look at them -- they may be worth some cash.

A set of 103 Pokemon cards from 1999 sold for $107,010 at auction last month. They were all first-edition English cards in mint condition, but included one very special card: a rare Charizard valued at up to $20,000, according to CNBC. 

According to the auction listing, Pokemon cards could become as important to modern collecting as rare baseball or basketball cards, made even more important by the fact that Pokemon remains popular with modern-day adults and kids alike. The listing also notes a similar set of Pokemon cards sold for nearly $100,000 in 2017.

So, check your Pokemon collections -- if you have a valuable first-edition card, there will be a small black stamp on the bottom left of the image of the Pokemon, which indicates the cards were published during the original release in 1999.

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