The only Master Ball available through normal play in "Pokemon FireRed" is given to the player by Giovanni in Saffron City. To obtain more Master Balls, the player must either trade with other players, import them from other games or use a cheat device.
The lone Master Ball in "Pokémon FireRed" is found at the top of the Silph Co. building in Saffron City. Giovanni, the President of Silph Co., gives it to the player after the player defeats him in a Pokémon duel. The player must also battle his rival Gary just prior to meeting Giovanni.
It is possible to receive a Master Ball from another player, and the inventory of individual Pokémon goes along with Master Balls when they are traded. A trade may be difficult to arrange due to the rarity of Master Balls, however. Players can also swap Master Balls between games from their own inventory. A Master Ball can be obtained in the games "LeafGreen," "Ruby," "Sapphire," "Emerald," "Colosseum" and "XD."
The final option is to use a cheat device, such as the Action Replay, GameShark or Game Genie. Codes for these devices may be available that allow a player to add extra Master Balls to his inventory.