I wanted to rent a car in Germany for a couple of days:  The price was €166.90.  The start date is in the top left of the picture, highlighted below. Tues, 3 Apr.

My plane times were a bit unhelpful for an easy drop off without wasting a lot of time at the airport to save on another day’s rental.  I wondered how much extra it would be if I actually added another couple of hours to the drop off time.  It would probably add a whole day, I thought.  I was right.  However, the price of this extra day shocked me:  it was minus €47.38.

Yes, It would save me €47.38 to hand it in an hour late, which was surprising.  So I wondered how many days extra I could book before it cost me more than the original 2 days.  Four?

Wow!  Even doubling the hire period would still cost me €22.30 less than hiring for two days.  How about a week?

WTF?! It is cheaper to have the car for an entire seven days than it is for two.

My conclusion is that renting from another place altogether would be a good option.