What exactly is Vroom Vroom car rental codes? I just tried using their code 299851 and go a better rate and upgrade with coupon code AU4234FDA. This was posted on the July Car Rental forum. Do I need to belong to something to use this? Has anyone else used this with success and not had to present a card as proof. I do not need any surprises when I go to pickup my rental. Please advise and let me know all details with this. Looking on line I see that this is a rental website to compare car rentals.