You cant in one day. The only way to get master balls without cheats is by winning lottery alot.
Note. Tip for lottery winning, just trade with lots of different people.
Clone your Pokemon and give them the master ball
You use action replay
get action replay then press L+R then look in the poke balls or items section and it should say you have 999 master balls
use a game shark and type "22671 master balls 99857=999
the only way you can get 999 masterballs by using cheats THE ONLY WAY!!!!!!!!!
Without using cheats you can't get 999 masterballs unless you are very very lucky and win 1st place in the Pokemon lottery 999 times
999 master balls and super exp up.
Not without hacking.
you dont
There is only one master ball in every poke'mon game per file. Therefor it is futile to even try to get more without using cheats. You could use a games shark or an action replay to achieve 999 master balls.
you get a life lol
run trough walks, 999 master balls, exp up super fast.