Pittsburgh has one or more gas stations available. These are places that sell fuel and lubricants for vehicles. The most commonly used fuels are gasoline, diesel and electric energy. Prices for each can fluctuate, depending on market conditions, and have to be put on display at the station. Such stations also may have a small convenience store attached. Payment has to be usually done in advance to prevent drive-offs. It can be done by credit, debit, ATM cards, fuel cards and fleet cards. The kind of service offered may be either full service or self-service. In the former, the customer himself operates the pump. Minimum service would mean the attendant would only fill in the gas and collect payment. For full service, the attendant fills in gas, often wipes the windshield, checks the oil level and tire pressure of the vehicle, and collects vehicle along with a small tip. Many states do not allow self-service for various reasons, but full service stations are increasingly rare, even in Pittsburgh. Other facilities at gas stations include toilets, air compressors, stores with food, beverages (sometimes including liquor), and often cigarettes, lottery tickets, motor oil, and auto parts. A fast-food outlet may also be there.