That's easy, here's what you do...
This means you only have one Car, so it has to be reliable, which means it has to be new and under warranty, an unreliable Car can cost you your Job, try calling work once a week to tell them you won't be coming into work because your Car broke down again.
Sooo...Buy a Toyota/Honda/Hyundai/Scion/BMW CPO for $30K including tax and licence.
Lets say you have a 48 month warranty, so you have to sell the Car when it expires.
If the car loses 50% in depreciation, then after 4 years the Car will be worth roughly $15,000. In the meanwhile, you open a savings account and pay yourself back $312 pm. It's like financing at 0%, but if you fall on hard times, nobody can tow your Car away.
After 4 years, you trade the Car in on a new one, give them $15,000 and you're back into a new Car.
Remember, use your savings like you're borrowing from a Bank, pay yourself back.