Here are some factors that can affect the value of a Pokémon card:
* Rarity: Some Pokémon cards are more rare than others. The rarity of a card is determined by its print run, which is the number of copies that were produced. The rarer a card is, the more valuable it is likely to be.
* Condition: The condition of a card is also important. Cards that are in mint condition (meaning they are free of any damage or wear) are more valuable than cards that are in poor condition.
* Popularity: The popularity of a card can also affect its value. Cards featuring popular Pokémon characters are more likely to be valuable than cards featuring less popular characters.
Here are some of the most valuable Pokémon cards ever sold:
* Pikachu Illustrator (1998): This card was given to winners of a CoroCoro Comic illustration contest in 1998. Only 39 copies of the card were ever produced, making it one of the rarest Pokémon cards in the world. In 2021, a copy of the card sold for $5.27 million at auction.
* Charizard (First Edition, Shadowless) (1999): This card is part of the first edition of the Pokémon card game, and it features a shadowless Charizard. Only a small number of shadowless Charizard cards were produced, making them very valuable. In 2020, a copy of the card sold for $320,000 at auction.
* Blastoise (First Edition, Shadowless) (1999): This card is also part of the first edition of the Pokémon card game, and it features a shadowless Blastoise. Only a small number of shadowless Blastoise cards were produced, making them very valuable. In 2021, a copy of the card sold for $312,000 at auction.
These are just a few examples of the most valuable Pokémon cards ever sold. The value of Pokémon cards can vary widely, and it is important to do your research before buying or selling cards.