Just bought a 2011 Prius with money I've been saving up for the past 2.5 years. It's a funny story actually.
I had a lease on a gas-guzzling Toyota Venza (SUV), prior to learning about MMM and early retirement. The lease was actually up in September but when I took it in for the 20,000 mile service at the dealership where the lease was held they apparently decided I was so far under my maximum allowable milage before penalties accrued (36,000) they wanted the car back. They actually "bought" the car, paid off the remainder of my lease and gave me a little bit towards the next car I wanted, a Prius.
I was so under because I've been taking the bus to and from work everyday since I decided to become FI. This not only saved on gas, wear and tear, and insurance but led to the above happening. Now with the Prius its actually cheaper (though probably not as enviro-friendly) to drive into work than take the bus. I'll occasionally supplement with bus travel (and eventually bike, though Houston SUCKS for that). But one month in and I've only filled the tank once!