As fall road trip season is officially underway, a new study shows just how different car rental prices can be around the country. When it comes to the most expensive city to rent a car, travelers will find the highest price ins Little Rock, Arkansas, according to a new study from Cheapcarrental.com, which compared prices at 100 different U.S. airports from September to November. The average rate for the cheapest car at Little Rock’s Bill and Hillary Clinton National Airport (LIT) came in at $95 per day.