Rent here at your own peril
I booked a car with Rentalcars.com. On arrival at AVIS told me that the booked rate is just a part of what they will charge me, and that they always do business like that. They blocked my creditcard as a deposit. The car had more than 20 scratches. On return, they claimed I caused a new scratch under the driver´s door. In short, without the scratch they would have charged me 300% of the booked rate. With the "scratch", the bill was 1700% of the quoted rate.