Living in southern California, we don't have much choice except to use a car for most of our transportation needs. Also, while we live in the city, my wife's work is about 33 miles north, in the 'burbs. Luckily, being a uni lecturer, she only has to make the trip two, and sometimes three, days a week.
We bought our car, a 1998 Honda Civic, in late August, and since then we've driven 6,529 miles* (10,507 km) on 186.8 US gallons (that's 707 litres, and 155.5 imperial gallons), at a cost of $US 470.10.
So, our mileage has been:
35 mpg (US)
42 mpg (Imperial)
14.8 km/litre
The cost has averaged out to about $94 per month, and about 7.2c per mile.
* About 1,600 miles of that was a trip to San Francisco for the Christmas holidays. It's about 550 miles each way, plus the driving we did while up there.