Sorry - but you seem to have your ports mixed up. I am not sure if you are sailing from Port Canaveral and flying out of Fort Lauderdale, or if you are sailing out of Port Canaveral.
there is a big difference in distance.
However, I just rented a large car in Ft Lauderdale - I had it for 8 days and it only cost me $248 - complete (plus gas). It was big enough to carry six people and luggage.
Florida is cheap for rental cars because a lot of people drive and drop them there (apparently).