If you want to have your own freedom in your vacation and travel freely,  hiring a car is the best way to do it though driving in a city such as istanbul can be a big trouble due to the complicated roads and traffic jam made by millions of car. But if you still insist on driving in İstanbul, you can hire a car after arrival to Istanbul Ataturk airport from the World wide famous car rental agencies offices ( National Aloma, Europ Car, Hertz, Budget travel, Avis etc..)  located in the Istanbul Ataturk airport.  You can also make your own arrangements and booking via other companies before  arrival.

 Here is the information about  renting a car in Turkey.

 Feel Free to contact me for any questions.. thetouristguide@hotmail.com