This trick requires completion of the game. Play on Mayhem III offline. If this exploit still does not work after disconnecting from the internet and playing offline, make sure to delete all patches/updates to the game. Spawn in Sanctuary, and go to the Mayhem Board. It also helps if you are Level 50, as you will get bigger payouts the higher your level. Then, travel to a new location anywhere on any map. When you return to Sanctuary, all the money payouts at the slot machines are $1,000x larger. To get a lot of money, keep playing until you get a huge three-cash payout to get around $500,000+. However, since that is pretty rare, you will need to save up some money before attempting this. Try using the Tink Hijinx and Cash Trap slot machines, as they are right next to each other, and you can keep spinning for as long as desired.