Duplicate Pokemon with a masterball attached to them.
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 can get 2 Master Balls in both versions.
you can get 1 master ball
i masterball
one
1
1
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.
I think you can get only one.
Only one.
XD
one or more by trading with Pokemon holding a master ball