I would ask your T if he's willing to push the balance forward a bit, especially because you won't be seeing him the first week of May. Could you see if you could get a cheaper rental car? Not sure how many options are in your area (like how many rental places). but maybe try shopping around, as $80 seems really high. Are you buying the insurance for the rental? You generally don't have to, assuming you have your own car insurance. If it's the same cost though, it does seem better to rent the car than to deal with the guy who was giving you rides.