Unless you can find a store that sells the old games and systems and happen to be incredibly lukcy they might have a new copy. However you're best bet is to try second hand pawn brokers like Cash Converters you might be able to pick up a copy from their.
Other than that try the good old eBay but be careful as their are a lot of fakes online that you wont know are fake until you get a hold of them.
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 Groudon in Pokémon Crystal.
You can find it in Pokemon Platinum, Pokemon Crystal, Pokemon HeartGold, and Pokemon SoulSilver.
You cannot find Squirtle in Pokémon Crystal.
you find all the Pokemon
There is no such thing as a Crystal Onix in the Pokemon games series. It was only in the Pokemon anime.
you will find it north to cherrygrove, on route 30
You could get a shiny Pokemon for crystal but you need luck to catch one ("_")
in ice path in johto.
First, you have to find them, then, you have to battle them, then, you catch them.