what best places to earn money In ORAS? [duplicate]

Solution 1:

Outside the safari zone in the fence maze area, there’s a guy who gives you 10,000 for every win after you beat the elite four. With an Amulet Coin, Happy Hour Smeargle, and Money O-Power lvl 3 rewards 120k If you keep playing and rematching him for a hour (every 10/15 minutes IG) you should be able to get 500k+ :)

His name is Walter and you know you're challenging the right guy when he says "I've traveled the world's four corners with my Pokemon.”