One thing about moving so often: some times you can't take your cars with you, or you can take one car but any extras. As evidenced by the car sale lots on every post and base, a lot of car buying and selling happens when people move.
Our family has always found this a little extra tough because there are six of us. There are plenty of cars that will hold our family, but there are even more than will not hold our family. Particularly overseas, where most people are looking for easier parking and better gas mileage, we can't be sure that we'll arrive at a new base and be able to find a great car quickly.
You're probably guessing that I'm going to tell you about a new website that will make car buying and selling easier than ever. You are right! PCS Autos is a free website that allows users to post cars by specific base location. Created by an active duty Air Force guy, PCS Autos allows you to post your car for free, and keep driving it while you are trying to sell it. No more paying to put it on the base lot and then being stuck carless. I imagine that it will also be a lot easier to organize "we'll sell the car to you on this date" type deals as well. Just the benefit of being able to check out the car situation before you arrive at your new home makes PCS Autos sound great to me.
PCS Autos is pretty new and there aren't yet a bunch of cars listed, but I feel confident that it is going to grow quickly. What a great resource!