When you PCS overseas, govt will store your car at no cost. Indoor heated/cooled storage, they claim to start and move it once a month. Delivered to your next homeport or you can pick it up and drive it. So even if you buy a beater, you'll have something to drive when you get back stateside until you have time to get something more permanent.
I did it for 2 1/2 years and had zero issues upon return. Just had to put in a new battery after I picked it up.
We were in Japan before Germany, so I know about the storage. We did have a dead battery when we received the car in Germany (shipped from the storage place in San Diego when we left Japan), but other than that it was fine. We have that car now in Germany and it will be shipped back to San Diego. But I may have found a job for our time there, in which case we really need two cars. So this would likely be a second car, with the first one going to storage, again, when we leave for Japan. It's already old (2000) and will be 19 years old by the time we return from Japan, but it seems worth storing so we have something to drive when we get back, as you mentioned. Even if we sell it 3 months later, it buys us time to car shop.