Several years ago we rented a Buick Le Sabre in Washington DC and drove it for 11 days, turning it in at Orlando Airport, for about $160 including all fees. But we also has $75 one-way seats to Dulles Airport and the taxi home was about $40.
But unless you can get a repositioning, it will cost a lot to do a one-ray rental.
(Note that within Florida one-way drop fees are not legal for rentals fully within the State, so a person could rent in Pensacola and drop in Miami (about 700 miles) with no drop fee.)