Last month, I rented a car from the Dollar location at the Wyndham hotel in Downtown Disney. They offer a free shuttle to pick up and drop off at your hotel. It is arranged a few days before the rental. I picked up there but returned to the airport - it cost me $11 more than renting from the airport. I was able to use Magical Express and have them transport my luggage.
Another option is from
Alamo at the car care center.