First get the amulet coin from mom and then level up your pokemon so that they are at least level 60 and then catch kyogre to make it learn ice beam. Give dragonite the amulet coin.
Get a level 100 pokemon preferably one with a ton of attack i usually use dragonite get an amulet coin.
How to get money fast in pokemon alpha sapphire. Save your kyogre until the dragon master. Go to the elites with your dragonite holding the amulet coin and before each battle use the maximum prize money o power after each battle you will get a ton of money. Max out the prize money o power.