You don't. They're a one time item. The only way is to trade for a Pokemon holding one with your buddies.
unfortuanatlly not
Use gameshark codes.
one or more by trading with Pokemon holding a master ball
use an action replay
Kurt can not mak a master ball unless you hav an action replay code to make him make master balls
you use mean look then through master balls use them or use a utra ball.
Canalave City and Pastoria City
You need an AR then go to codejunkes.com tipe in Pokemon heart gold or soul silver then find the code for 999all pokeballs
You can get 3 master balls in soul silver and heart gold with using the 999 master ball cheat. I DO NOT know the cheat code.
you can't but you can use action replay or game shark or win the lottery in a building in goldenrod
http://www.neoseeker.com/Games/action_replay/
you use action replay