I recently rented a car from Avis Rent A Car, but only needed it for driving to a hotel from an airport, back and forth from the hotel to work daily, a trip of less than 2 miles, and finally back to the airport.
When I first acquired the car, the needle on the gas gauge was a distance past "F" (full). By the time I got back to the airport, the needle was still past "F", but not quite as far as originally. I had seen no reason to fill it up, since it would have taken considerably less than a gallon.
When returning the car, I was asked by Avis if I had added gas. I told them "no". The gas gauge still indicated full. When all the charges were tallied, there was a "Under 75 Mi Flat Fee" charge indicated at $13.99. I was told that if I had put gas in the rental car, and been also been able to produce a receipt that indicated any amount of gas put into the car, this $13.99 fee would not have been charged by Avis Rent-a-Car.
I'm sure a couple of bucks or less would have sufficed, although I was never notified of any of this when I first picked up the rental car from Avis. There were other crazy fees as well, but this was the most outrageous fee--and feels like a ripoff scam. It used to be standard that you were charged for gas if there was at least an eighth of a tank consumed; that aside, other car rental companies require that it meets the mark of when they provide the car (i.e. 1/2 tank, F (full) tank. When customers return a rented car, they get no credit back for accidentally surpassing the car's fuel hash mark by a small variance (i.e., slightly past Full); this is incredulous that the car was F (full) when leaving the rental yard, and F(full) when returning, yet I was still charged $13.99 for a fee I had never been told of.
No matter how little you use a rental car from Avis, be sure to add gas before you take it back to the rental yard so you don't fall into this trap. This is also a fee that Avis needs to realize is a major scam for their customers--no other rental place does this, and it's a fraudulent fee and ripoff to the consumer.