Simply put: use your feet. Remember those days in summer where you'd walk or bike to your neighbor's house? Or make it a day trip up to the park? As a kid growing up without an older brother or friend to drive me around, I was left with few options and biked everywhere. My grandmother, who came from a foreign country and was scared stiff at the idea of operating her own vehicle, had spent over 40 years in America without a car. As she was my caretaker most of my childhood, I realized the importance and thriftiness of using public transportation and walking.
I took that mentality through high school, through college, and so forth. I had a car for a brief time while 60 miles away from home, in college, but I soon stopped using it and took the bus. It was not only because my car was not in its best shape, but it was cheaper, too (especially in the summers, talk about a $2 ride versus the gas I burn). What's even better is that these alternative modes of transportation has always been tried and true. Walking and biking are forms of some exercise, so I am still as healthy as I was in my youth. I can still run up a flight of stairs like a 5 year-old without losing my breath, and happily stroll for hours on end.
It is true that where I live (southern California), public transportation isn't exactly the best thing around. Some people may moan and grope about walking on a hot summer's day but my grandma used to simply take out her black umbrella and shield me from the sweltering glare. I was really embarrassed about it at first but after seeing 5 sweaty, miserable kids walk past me I realized how dry, cool, and comfortable I was. Not to mention that my grandmother came from a hot country, so I should trust her practices.
I remember taking the train up to LA and passing by hundreds of cars from the 5, even if we were only going 50 miles per hour. Although taking the train or bus requires some planning, that's exactly the point of saving yourself a few bus and the headaches of traffic. Let's start walking!