It was very easy to book a car, even before arriving in Belgrade. The minimum rental period is 3 days and the prices differ from the prices on the website, please specify. The second driver was added without additional charges. The registration took 10-15 minutes. And no deposit! The car was given with a minimum of gasoline, filled with a full tank, but in vain. We went to Republika Srpska (about 720 km), half a tank was enough. The car, although experienced, gave us a great ride! (Citroen C4, automatic, diesel, if anything).