you can get 1 master ball
Only one.
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!
You can get 2 Master Balls in both versions.
you only get like two you get one in dragons den located in blackthorn city and professor gives after you get a few gym badges you can also catch legendery Pokemon with an ultra balls if you you get the Pokemon to get parylyzed and get it up to red or yellow.
1
i masterball
1
one
You can clone a Pokemon with the master ball or trade it to a friend and keep starting over until you're satisfied with the number of master balls.
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)
Duplicate Pokemon with a masterball attached to them.
I think you can get only one.