"Pokemon FireRed" is a remake of the original "Pokemon Red." "Pokemon FireRed" was released for the Game Boy Advance along with "Pokemon LeafGreen." In the game, you can find rare candies scattered throughout the world, although as their name implies, they are very rare. Thankfully, you can use various cheats to receive unlimited rare candies in the game.
You can use a Game Shark cheating device in order to receive unlimited rare candies in your PC. First you will need to insert the GameShark into your Game Boy Advance and then insert your copy of "Pokemon FireRed" into the GameShark. Turn the Game Boy Advance on and enter "820258400044" at the GameShark code screen. Press "Start" to begin the game normally. Travel to the nearest Pokemon Center and check the PC. Go to "My PC" and you will have an infinite number of rare candies. Although the number of rare candies may be gibberish like "x8B9," you can take out as many as you wish and never run out.
An Action Replay device is similar to a GameShark but is made by a different company. The process and idea is the same, although the code is different. Place the Action Replay device into the Nintendo Game Boy Advance and place your copy of "FireRed" into the Action Replay. Turn the device on and, when prompted, enter "77db5497 d7ee8c96" at the code screen. Start the game normally and make your way to the Pokemon Center that is closest to you. Go to the PC and take out as many rare candies as you wish.
Using a device such as an Action Replay or a GameShark to modify your game file can result in corruption of your saved data and, in some cases, even erase the entire game file itself. In addition to the possibility of losing your data, your game will become ineligible to use in any Nintendo Pokemon VGC tournaments. If you will not be entering any tournament, you do not need to worry, but if you are, be aware that Nintendo uses a game checker before every tournament on every participant that verifies whether the game has been modified or not.
Although this method can take quite a while, this is the safest way to obtain infinite rare candies as it will not mess with the saved game file so there is no chance of corrupting the data. Take any Pokemon that knows the "Pickup" ability. Zigzagoon is the most common Pokemon that knows "Pickup." Travel around in the tall grass and Zigzagoon will have a 5 per cent chance of picking up a rare candy. The number of items picked up increases as Zigzagoon's level gets higher. Consider using repels in order to prevent any battles from occurring while you are trying to obtain rare candies.