What is the cheat code for master ball?

Answer 1

No code required.

Meet your new Best Friend, MissingNO

When using this method, you will obtain 128 of whatever item is in the sixth slot of your bag. This is because the PokeDex value that determines if a Pokemon has been seen, 128, is used and is shown as the amount of that item. For this to work, you don't have to catch Missingno, you just have to encounter it. You can defeat it, capture it, or run away from it. Missingno issafe to capture. It does not pose a threat to your save file, despite what you may read elsewhere. Missingno has a 37/100 capture rate. It will only work 37 times out of 100.

First talk to the guy in Viridian City that tells you how to catch pokemon. Tell him you aren't in a hurry, and when he's done fly to Cinibar Island and use surf to surf on the half water half land shore area. Here is your MissingNO.