Booty is the secondary currency in Oasis.
You can get Booty by completing quests or by buying it with Rays at an ATM. You cannot get a refund for booty (exchange them to get your Rays back) so make sure you buy the correct amount.
You can use Booty to access special in-world features like tattoos, change rooms, lap dances and more. (coming soon)
You can view your Booty balance in-world underneath your mini-avatar