Yes, like bigfatk said, you can start renting at 21. Depending on the city and the car rental place, the fee can be anywhere from $10 to $25 (or more). Sometimes Enterprise is the cheapest on this fee but not always; the last car I rented from Avis. Just check around to get the most bang for your buck. (If you check the company's policy page it will tell you their under 25 fee).