The two most consistent costs to owning a vehicle, outside of a car payment, are insurance and fuel. The budgeting rule for this combination is 8-10% of take-home pay. Depending on your transit, where you live, and your driving history, insurance and fuel costs can vary widely.
Another factor to consider is that the combined insurance/fuel cost is variable, and will likely fluctuate from one month to the next. Then there are the taxes, fees, maintenance, and repair costs! My advice to any first-time, car owner is to *take a long, hard look at the total cost of driver ownership (TCD) before purchasing any vehicle.
Edmunds.com provides a pretty great calculator here.
Contributor: Alex Lauderdale founder of educateddriver.org