You spontaneously want to travel longer than just a few kilometres? No problem. You don't have to decide before the trip and you don't have to book anything extra, you automatically get the best rate.
As soon as the price slips into the 6h rate, the car is yours. For 6 hours and 75km.
For an S- or M-size car the 6h rate is 35€, an L-size car costs 59€. With parking included. If you drive more than 75 km, each extra kilometer will cost you only 0,29€.
If you drive longer than 6 hours, you slip into the next package, the daily rate.
With the daily rate, you'll be on the road a full 24 hours and 150km. With parking included. If you keep driving, each extra kilometer will cost you only 0,29€. An S- or M-size car costs here 59€, an L-size car 99€.
If you use the car longer than 24 hours, the next package (6h rate) is automatically booked for you, and so on.
A calculation example:
On Friday evening at you would like to drive to the Baltic Sea together with your best friend. There, you drive around a bit and enjoy the weather. After a nice weekend, you arrive back in Berlin on Sunday afternoon. You were on the road for 44 hours and drove a total of 470 kilometers.
That is equal to 2 times the daily rate (300km incl.) and 170 kilometers in addition.
-> 2*59€ + 170*0,29€ = 167,30€ for a spontaneous departure, no cleaning, no refueling, no stress...
Oh yes, and you two were on the road, so 83,65€ each. Fair is fair, right?
You can find detailed information about the prices of the individual vehicle classes under Rates.