The smartest financial decision I ever made was buying a $3k 10 year-old Honda Civic when I started my first "professional" job. I bought it with cash, using my sign-on bonus, and drove that car for three years before I sold it for the same price and upgraded to something a little bigger for my long commutes.
I have a friend who is an attorney and drives a Prius. The other attorneys mock her for this choice, but they would mock any car that sells for less than $50k. You can't please those people and be Mustachian, so do as my friend does, and say fuck 'em.
My recommendation:
Buy a cheap, economical car that will hold it's remaining resale value. Research maintenance and particular issues for your make/model/year, have that addressed by a competent shop, do the required maintenance going forward, take good care of it so you can sell it and enjoy the cost savings.
There are lots of options out there.