Firestones are evolution items that allow certain Pokemon to evolve. You can obtain them in the following ways:
* Find them in the wild: Firestones are found in tall grass or caves. You can also sometimes find them as rare items in certain locations, like the Safari Zone.
* Trade for them: Other players might be willing to trade Firestones for other items or Pokemon.
* Win them in contests: You can sometimes win Firestones as prizes in Pokemon Contests.
While you can't buy Firestones directly, you can find them through various methods within the game. Good luck on your hunt!