[dubb93]

My oldest son (6 year old) recently brought me a bunch of Pokemon cards that he had been saving from McDonald's Happy Meals. He has apparently been collecting his and his two brothers cards and keeping them safe somewhere in his room. When he brought them to me he asked if we could play the game. I know just enough about Pokemon cards to know that you can't play with just like 30 cards from McDonalds. When I try to search on google it seems all I've found so far are either the rules of the game (which confirm we don't have enough cards) or guides on how to collect them and make money. I'm looking for neither of those. My question is how the heck do we actually start playing?

What do I need to buy so that we both have a full deck so we can play each other?