The Twenty Dollar Trick works for more than just hotels, we have heard successful reports of our readers using it to get a free upgrade at national car rental chains. Why not pay for a standard rental car and get a free upgrade to a luxury car of SUV?
Using the Twenty Dollar Trick for renting a car we would suggest not offering the $20 bill directly to the clerk but just flashing it to them. If they do provide an upgrade you can than hand them $20 bill. This ensures that you will only have to pay $20 if you get an upgraded car.