Duplicate Pokemon with a masterball attached to them.
one
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
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.
Only one.
I think you can get only one.
XD
one or more by trading with Pokemon holding a master ball