I have rented many times within the state of Florida, picking up at one location & droppping off at another. It is my understanding that it is against state law to have a 'one-way'/'drop-off' fee.
We have rented from Miami/returned to Orlando, rented from Tampa/returned to Orlando and rented from MK Car Care Center/returned to Orlando.
On our upcoming August trip I am thinking about picking up a National car from the MK Car Care Center location(no "Airport Concession Recovery Fee"!). I'd then drop-off at Orlando International after keeping the car for part of our stay, paying for a *week*...no nasty extra day charges. *But* get a towncar service for the initial trip from the airport to our WDW resort. Believe it or not this will be cheaper than renting a car for our 8 1/2 days. (I'll admit, not *much* cheaper, but still

) My idea of a treat is being met at baggage claim, taken to a grocery store to pick up some snacks & such, being at my resort within an hour of deplaning & then picking up a rental car later in the stay for freedom when we need it. Hey, our DD is 12 & I *like* having a car for that occasional trip to the Urgent Care Clinic.
To the OP: If you're thinking of renting from somewhere else & then returning to a location in/near WDW, I think MouseSavers has (somewhere in the Rental Cars section) the various company locations in/near WDW. If you rent from National or
Alamo(sister companies), you can get a complimentary shuttle from your WDW(on-site) resort to the rental location. The two closest are at the Magic Kingdom Car Care Center and at the WDW Dolphin(at least I *think* it's the Dolphin...)
Just check out MouseSavers for all sorts of hints/tips/codes if you're thinking of renting a car when you're visiting WDW.
Hope this helps,
agnes!