I have only been truly car-free for a period of about 2 months when I moved from the city (I didn't have a car there but my mom did...and I didn't need one because of public trans so I don't count that as car-free really). Once I moved to the suburbs when I was 17, I needed one. I rode my bike to work (about a mile) for 2 months until I saved enough to be able to pay for my car insurance and then I was able to find a better job.

Unfortunately, living in the American suburbs really precludes one from going totally car-less. Everything is much too spread out and doing a 20 mile round trip on a bike to get groceries is a bit much.