Nothing else. Almost any $5 cigarette lighter charger will work fine. (I don't think I paid $10 for both of mine together, bought at different times. It's basically about 5 cents of plastic, 10 cents of metal, 2 10 cent USB ports and a 25 cent electronic part. If you buy the stuff wholesale (which the manufacturers do), it costs about 15 cents per charger. There's no reason to pay $15 or more for one - inside, they're all the same.
The same cable you use for charging from the charger that plugs into the wall will work with the charger in the car. You might want to get another cable just so you don't have to remember to keep carrying the cable back and forth - leave one in the house, one in the car. I also usually keep a little plug-in charger and a cable in my pocket - I spend long hours in doctors; waiting rooms, and sometimes you can run the battery down before you get called. (The local hospital ER waiting room usually has every single wall socket being used to charge a phone. Those ads for the S5, showing everyone sitting on the floor plugged into a charger, are going to become a common sight all over, not just in airports.)