You can only get one or use cheat
1
one
There is only ONE I believe.
You need to transfer from Emerald the mb. You give (Emerald) the Pokemon you are going to clone the master ball (hope you have 1) and then do the battle tower glitch and voila! Here are your master balls. You can use this as many times as you like!
therer is one that you get in the team magma hideout but you can get more if you give it to a Pokemon to hold and clone it. THIS ONLY WORKS IN EMERALD IN THE BATTLE FRONTIER
Attach your master ball to ONE POKEMON, next CLONE that Pokemon for how many master balls you want. Next detach them, and release all the clones (if you want)
you cant measure out ultra balls to equal master balls. master balls are just a lot better.
You can't buy master balls in any version...In some point the professor will give you only 1 master ball so you need to use it wisely. You could get as many master balls as you want only if you cheat.
You can get 2 Master Balls in both versions.
INFINITY MASTERBALLS just do my trick Trade pokemon for pokemon holding masterballs take them away and trade for your pokemon back
Well you can get a action replay code and use it to get 999 Master Balls
1 Master Ball