Easy way to earn money on Pokemon Omega Ruby/Alpha Sapphire?

I've recently been attempting to complete the Hoenn pokedex. I need a lot of pokéballs and ultra balls to catch em' all. If anyone knows an easy way to do this please simply explain it. I believe that repeatedly challenging the Elite Four may work, but I don't really want to do that.

You should give Amulet Coin or Luck Incense to your lead Pokemon.

O-Powers can help you, too. Prize Money Power that raises the money gained from a trainer battle, and Bargain Power that decreases the amount of money you have to spend on items.

Earning Money:

You can use these to earn more money:

1. Amulet Coin* or Luck Incense** (Make your lead Pokemon hold them, they do not stack)
2. Prize Money O-Power***

You can make the best use of them by re-challenging:

• Trainers (Check the AreaNav's 'People' function to find them)
• The Elite Four (also unlocks other goodies)
• The Food Court in Mauville City.
• Secret Base Trainers (AreaNav 'Bases')

Saving Money:

Having more money is all well and good, but what about spending less as well?

• Use Bargain O-Power for discounts (half-price at level 3)
• Buy Balls in groups of 10 each, to get the bonus Premier Ball as well.
• Pickup Pokemon will occasionally find a Great or Ultra Ball, depending on their level.

Catching Pokemon

Now, onto the crux of the issue, catching Pokemon efficiently, so as to waste less Pokeballs:

• Use a Catcher Pokemon. Sleep + False Swipe will make a lot of Pokemon easy to catch, even with regular Pokeballs.
• Use Catching O-Power.
• Make use of Quick Balls and Timer Balls****.
  • Quick Balls have a greatly boosted catch rate if thrown as the first move. Good for Pokemon that tend to flee.
  • Timer Balls have a greatly boosted catch rate if the battle has gone for 10 turns or longer. Good for Pokemon that don't want to stay in their Pokeball/Stay asleep

_{* You get Amulet Coin from your Mum after the 5th Gym Badge.
** You can purchase Luck Incense in Slateport City
*** O-Powers are unlocked through the 'Strange Men' in Mauville Pokemon Center. Keep interacting with them, exiting and returning to the Center as they leave.
**** Quick and Timer Balls can be purchased from Fallabor and Rustboro Marts respectively.}

The best method is:

• Get a Level 100 Pokemon, (Preferably one with a ton of attack, I usually use Dragonite)
• Get an amulet coin
• Give Dragonite the Amulet Coin
• Max out the prize money O-Power
• 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.