This achievement will probably one of the last you get. It will take a very long time to get so a lot of grinding will be involved. On average you will net 500-800 Scratch for winning a game and gaing bonus Scratch for combo shots, winning under five minutes, etc. If you loose a game you are looking around 200 Scratch. So you are looking arond 2000 games (if you win everyone netting 500 Scratch) or 5000 games (if you loose every match netting 200 Scratch). Realistically you are looking around a good 200+ hours playing single player.
If you can find a partner to do this with you could both earn 500,000 each and gamble it all on online matches trading the win each to both gain 1,000,000 Scratch. Remember to trade it back to each other afterwards though so you can both use that money towards the "Jet Setter" achievement.