Drag each car to a pump of the same color. Click on the pump to start pumping. If the customer requests something from the store, click on the item and then on the customer. When the customer's tank is full, click on the car to pick up the money and then on the cash register to put it away. Serve the customers as quickly as possible (before they get upset) to earn the maximum amount of money! Use the money you've earned to buy upgrades between days.