I feel rather strongly about this. I never bought a car that cost more than $10K until I had been an attending for nearly 3 years. The first car I bought as an attending cost $1850. I rode my bike to the hospital as a resident. I rode my bike or the bus as a medical student. This crazy idea that you have to pay a certain amount to get something reliable is wacky. You get a reliable car by buying a reliable car. There are plenty of reliable cars with 140K miles on them. I've got two of them in the garage right now. The money you save buying an older car can pay for a helluva lotta repairs, car rentals, whatever and still leave plenty left over.
Now, I don't buy $2K cars anymore, but I also make a ton of money, don't have any student loans, will have my mortgage paid off decades earlier than average, and have lots of money put toward retirement and my children's college. If I didn't have that stuff taken care of I'd be buying $2K cars still.
http://whitecoatinvestor.com/drive-a-beater-get-rich/
But you know what? I can't talk most residents out of buying a house and I can't talk most of them out of buying a car that is more expensive than they can really afford. So do what you want. But some of the best advice I ever got was to pay cash for every car you ever buy, and it has worked out well for me.