Always make sure to use the correct fuel type when you refuel. The two types of fuel offered in Iceland are diesel and gasoline/petrol. Every gas station will have both fuel types available. The Gasoline/Petrol is a green pump and is marked 95 okt. The diesel pump is black and marked diesel.
On the key chain is a chip from Olís and ÓB, Iceland's most common gas stations. By using the chip customers get a discount of 5 ISK per liter. The discount is available at any Olís or ÓB gas station, both at service and self-service stations.
How to use: To activate the discount at self-service stations customers, need to press the chip against a marked label on the pump. The price changes automatically when you start to pump the fuel. At service stations customers can use the chip when paying inside the station.