"If you rental involves less than 75 miles, we will automatically charge you $10.50 for gas upon your return. This charge will be removed upon presentation of a receipt for gas purchased."While I might have phrased this differently to stress the customer benefits it offers (the second line could be said in a more positive way), I think the actual idea/service is brilliant.
I'm sure a significant percentage of Orlando rentals are to/from Disney with perhaps one side trip. This would fall right at 75 miles. What could be better than saving yourself and time and search for a gas station when you are in a rush to catch your flight?
Budget isn't making a lot of extra money from folks who use close to 75 miles, but they are providing a desirable service at the right time and the right price. Maybe I'd save a dollar or two by filling it up myself, but the peace of mind knowing I don't have to and the time saved not doing so is easily worth that.
There are probably hundreds of opportunities to do something similar in other industries.