As has been pointed out, if you are worried about gas mileage, budget or not, RVing may not be the thing for you. My suggestion (what I do) is find what you want that does the job and buy it. Don't know that I've ever even thought about gas mileage when I was towing......except when I'm afraid I might run out of fuel...then I have the onboard computer telling me what mileage I'm getting and how for to empty!