Answer:
Car insurance. You pay monthly, hoping that you never get into a crash. If you do, it pays for repairing or replacing your car, and/or the other car/s involved.
Routine maintenance. Every 35,000 miles driven (or so), you need new tires. Every 3-5,000 miles driven, you need to get the oil changed. You need to replace brake pads, windshield wipers, etc.
Gasoline. The price varies, and depending on how big your car's engine and gas tank is, that can get very expensive.
Unplanned repairs. Dead battery, car overheats. You have to get the car fixed so you can get to work/school.