Two, one given to you by Cyrus after you defeat him at the Galactic Veilstone building. And you can get another one by matching 5 numbers in the lottery in Jubilife City.
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.
You can only get one or use cheat
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 cant measure out ultra balls to equal master balls. master balls are just a lot better.
You can't buy master balls in any version...In some point the professor will give you only 1 master ball so you need to use it wisely. You could get as many master balls as you want only if you cheat.
You can get 2 Master Balls in both versions.
1 Master Ball
Well you can get a action replay code and use it to get 999 Master Balls
you can get 1 master ball
2
in all of the Pokemon game, the way to get a master ball is to beat the boss of the criminal organization and you will get this as a reward. but i heard that you can get more master balls in pearl, diamond and platinum in jubilife city in the tv station by that lottery stand but i think it will take a lot of trading with many trainers to get one master ball just to match the numbers. but i think there is a cheat to get A LOT of master balls. I hope that this answer is helpful to many owners of these Pokemon games.
Just one