Mears .. on the web.
But if you have a few people in your party consider a one way rental. It was very cost effective. They pick you up from the ship in their shuttle and take you to the rental office. Then you can drop the car off at the Orlando airport (this can be done both ways) the cost is about the same as two people worht of charges for the shuttles.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013