In most cases it is only possible to rent a car if you have a credit card. Alternatively you are required to pay a deposit that varies from 8,000 CZK to 50,000 CZK depending on your destination, and duration of the rent. You also have to look very carefully at the insurance. If the rental is cheap it may be because your own risk is high, but you may also end up having to pay for a part of a car repairing, even if you have paid a high insurance. The smaller local firms may have extra obstacles, for example they may demand a Czech guarantor, or have special demands regarding citizenship.
Most rentals also have manual transmission.
It can be difficult or expensive to get a rental car for trips to the former East-bloc, because of the risk of theft. It may also be difficult to rent a car if you are under 21 years olds and some companies requires you to be at least 25 years old. A Rent Car spol. 2,438 CZK Min 21 years old. Driver license min.