you cant unless you have an action replay and use the 999 ball code.
you get it at the begging of the game at the first poke mart you go to. you have to at least buy 5 poke balls to get it. that is the only way i know of. hope this helps.
You can't buy Poke Balls during a battle, unfortunately. The only thing you can do is run from the battle or faint the Pokemon, then buy Poke Balls and encounter the rare Pokemon again (or in the case of a legendary, restart and try again, assuming that you ran out of Poke Balls during the battle).
buy them from the poke mart if you have a lot of money.
go to a poke mart go to a poke mart
depends is it the poke balls cuz all u gotta do is buy them at the poke mart
You buy them from the poke store or trade apricorns to Kurt and he makes them
You can buy them at the Pokemon mart at the Pokemon league. I buy my timer balls, heal balls, etc. at the Pokemon mart in canalave city
Buy them stupid
You buy them in the Pokemon markets.
You cannot buy max revives at any shop. You just have to go look for them in poke balls.
You buy them at the poke-mart once you have enough badges
Catch them with Poke Balls. Or buy the game if that's your question.