Do NOT go with Fox's prepaid fuel option. As opposed to one of their major competitors that I usually use, Fox charges you for more than a full tank of gas no matter how much fuel you actually use. Mind you this is not explained anywhere in advance, either when you rent the car online, on the paperwork when you pick the car up, by the clerk who offers you the option, or when you return the car (at which time it's too late, as it is a nonrefundable charge). We had only used a quarter tank by the time we returned the car, and I expected they would charge me the prepaid rate to replace the quarter tank I used. Instead of charging me $12, however, they charged me $54, more than it would have cost to fill the entire tank at $3.10 per gallon (the prepaid price). The end result was I ended up paying double what it would have cost me to rent the car and top off the tank myself. That's the last money Fox will ever get from me.