When you are PCSing to Okinawa, you cannot bring your vehicle with you. That means when you get to the island you will have to buy one, if not two cars upon arrival.
When you get to Okinawa and have started to settle in, you start getting antsy to learn how to drive on the other side of the road and to get out on your own. First things first, you have to take a driving test in order to get a license. Just study the packet that they give you and you will be just fine.
Then, you need a car. Buying a car is super easy here, but it does take time and knowledge. Think about it, tons of people are leaving the island and can't take their car with them. They are in a huge hurry to sell, since they can't have cars in their name when they leave.
So how do you go about finding the right car? First look at Okinawayardsale.com (bookoo). It's basically a Craigslist for Okinawa.
This way, you know what the prices are like, what kinds of cars are available, what kinds of features are important, etc.
Start by determining how much you want to spend. You can get by with spending very little if you don't care about how nice your car is. If you feel like your time on the island would be more enjoyable cruising around in a nicer car, that's fine too.
Decide what kind of car you want. Do you want something small and great on gas milage? Do you want something big to haul people and gear (scuba) around? Do you want something with 4 wheel drive so you can explore?
Once you have the big factors down, you can look at cars individually to see the pros and cons of each.
Things to consider: JCI, mechanics, exterior, interior, AC, tires
When considering the exterior, remember the conditions that cars on the island face. There will likely be peeling paint, rust, dents, etc. due to typhoons and salty air.
JCI is very confusing but neccessary. JCI means Japanese Compulsory Insurance. JCI is a must in order to drive the vehicle. It must be renewed every 2 years. They will inspect the car and you must fix the things on the car that don't meet the standards before you can be issued a JCI. JCI can be very expensive, so it is ideal to get the longest JCI when purchasing a car. You want to at least have a year left on the JCI, so you will only have to pay for it once while you are here on the island.
Other fees: Yearly road tax, title transfer, yearly insurance
The number on your license plate gives you an idea as to how much your taxes will be. You want your number to be high. It is ideal to buy a car with a 500 plate as opposed to buying a car with a 300 or lower plate.
So, when you are ready to find a car, start by looking on Okinawa Yard Sales(OYS) and the lemon lot. Some vehicles on OYS are also at the lemon lot. The lemon lot is a lot on base where people have paid a small fee to leave their car there to sell. The lemon lot and Okinawa Yard Sales are both good options. You can also go off base to a used car lot. We found that the prices at the used car lot were a significant amount more than the ones on OYS. The one good thing about used lots, all the cars come with a brand new JCI.
The key to buying a car on Okinawa is to negotiate. No one is actually trying to make money off of their car (except on the used car lots). They just want to get it sold without going to far under what it is worth or what they paid for it. Most people will take around $500-$1000 under asking price. Look for good deals. Some people are really desperate and will give you a great deal.
Before arriving on the island, Jake and I set our budget at $7000 for two cars. We thought that was pretty reasonable after doing some research on OYS. When we got to the island, we started by looking at the lemon lot. This gave us an idea of what was on the market and what different types of cars and features cost what. Jake and I agreed that we wanted one small car to zip around in and have low gas milage and one bigger car with 4wd to do some exploring.
We scoured OYS for about 4 days straight. We met with quite a few different people to look at their cars. Some people would not come down on price to what we thought was reasonable. Some cars were not worth the money or did not seem mechanically sound when we test drove them. After looking for awhile, we realized $7000 was way more than we needed to spend. That was a very nice surprise. We realized neither of us needed a super nice car, as long as it was mechanically sound.
We first found a 01' Toyota Will for $1,600 on OYS. After test driving it and checking it out, we offered $1,200. The paint on the entire car needed work, but it was mechanically sound and had very little miles on it. The seller agreed, and so we bought it.
A couple of days later, Jake heard back from a guy he had been in contact with about a 97' Mitsubishi Pajero. He had test driven it at the lemon lot and really liked it. It had a bit of wear and tear, but we thought it was a good car to have for rugged activities. The guy had originally been asking $3,500, and Jake offered him $2,200. We thought this was a good price because of the exterior damages and the JCI would be up soon. The guy told Jake he had an offer of $2,700 and would get back to him. The offer fell through and the guy had to get it sold because he was leaving the island that week, so he sold it to us for $2,200.
So if you do the math, we got two cars for the whopping price of $3,400. We were incredibly happy with this price and we are happy with our two cars so far. We have had a need for both in different situations.
So here are my overall tips for buying a car on Okinawa:
-Do your research. Know what cars are going for and how much you want to spend
-Take your time. Don't rush it or you may spend more than you need to.
-Look for deals. People here get in a crunch and need their cars gone. Wait for one of these deals to come along.
-Consider JCI (not like we did with the Pajero) so that you only have to worry about it once
-Negotiate aggressively. You most likely won't offend anyone, the worst thing they could do is say no.

**I know this post was long and boring, but I wanted to share this information with anyone PCSing to Okinawa