In Pokémon Omega Ruby and Alpha Sapphire, Premier Balls are given to you as a gift whenever you buy ten or more Poké Balls at once. And unlike in previous generations, you can now receive a Premier Ball by purchasing x10 copies of any Ball, not just regular Poké Balls.
Shopping for Premier Balls
For every ten of any Ball you buy at any mart, you get one free Premier Ball. So if you’re just trying to get lots of Premier Balls, you should stick to purchasing only regular Poké Balls, since that’s the cheapest way to go.
Unfortunately, buying twenty or more Poké Balls in a single purchase only gets you one Premier Ball. So if you want more, you have to make multiple separate purchases of 10 Poké Balls each time.
You can also get them on the Lilycove Department Store’s second floor, where Poké Balls are being sold.
Ball Mechanics
A Premier Ball has the exact same Catch Rate Modifier as a regular Poké Ball. Because of this, you might find it hard to catch high-leveled Pokémon with it.
Since it doesn’t make catching Pokémon any easier, it’s better to use Premier Balls on Pokémon you like.