Pokémon isn't only a gameboy game and a tv show anymore(well it's also lots of other stuff) but now it's a card game too. The card game is kind of like Magic: The Gathering, but it's based on pokémon and you need energy cards of the same type of pokémon to use thier moves. You can also evolve them and all kinds of other stuff. I think the card game is even more fun than battling your friends on the gameboy game. There is a total of 102 cards in the set, and there are trainer, energy, and pokémon cards. There are 3 different packs you can buy pokémon cards in.
The last type is the booster pack. It contains 11 cards with a mix of trainer cards, energy cards, and some common and uncommon cards. Only experts or people who only trade cards should buy booster packs so they can make thier own decks.