I found one the other day at Game, They're really hard to find now-a-days, but you can rarely find one at Toys-R-Us, Try looking there. Ebay would also be a great place to find Pokemon Crystal, since most people would rather sell their old GameBoy copy, rather than keep it.
There are no legal versions of Pokemon Crystal for anything other than Gamenoy Color. You cannot find a legal copy for Game Boy Advance.
You can't find it in the wild, you need to transfer one from a copy of Blue/Red.
In Pokemon Crystal.
What the hell is a Pokemon crystal
You can't find Charizard in Pokemon Crystal. You have to trade it from Pokemon Red, Blue, or Yellow.
There is no NPC who you can trade a Haunter to for a Gengar in Pokemon Crystal. To get Gengar you will need to trade with another player or a copy of Pokemon Gold, Silver or Crystal.
saffron, below the train station, upstairs
There is no Groudon in Pokémon Crystal.
You can find it in Pokemon Platinum, Pokemon Crystal, Pokemon HeartGold, and Pokemon SoulSilver.
Go to GameStop! I got mine there for ten dollars about three or four years ago, so it might be cheaper if you find it!
You cannot find Squirtle in Pokémon Crystal.
you find all the Pokemon