I had made a three day rental in Houston, Texas and was returning the car in Dallas. When I had made my initial reservation the estimated total was $394. This is a lot for three days, but I justified it to myself with the fact that this included a GPS and a second driver, and that I was returning the car to a different location.
When I dropped off the car in Dallas I was asked if I wanted to charge the rental to the same credit card, I said yes, and was then given a receipt for$650!
I am fortunate in this case to have taken a look at the receipt- normally I just put the receipt in my briefcase to expense it later. Of course I went to customer service to complain, they told me that I had been charged more because I was returning the vehicle to the airport rather than a regular location. This did not really make sense to me- they had changed the daily rate because I was returning it to a different place? I only had a car for three days, and no, it was not a Mercedez, it was a minivan.
The customer service people did change the daily rate and brought the rental down to $420 but said something about taxes that they could not change. I did not have time to stay around and argue but it did leave me thinking that it is a good idea to double check the receipt that they give you when you return a rental car.