Cash: This is the main currency used for purchasing new buildings and attractions for your island, easily obtained by simply running your already purchased buildings. Each new season you will start with $5000 cash in order to get started.
Tokens: Tokens are earned through Safes, Special Deliveries, completing missions, and can be purchased from the Store. Tokens are used to upgrade your Managers once you've found enough cards to do so.
Gems: Gems are purchasable from the Store and can be earned by playing Events, opening Safes, and some Special Deliveries. Gems can be used to purchase Safes from the store and profit boosters.