It depends on how many people you have. Personally, we prefer to rent a car one-way. There are several car rental agencies with a couple of miles of the pier and they provide complimentary drop-off service. The price will depend on the company you use and any discounts you may be entitled to, but we've paid as little as $35 each way. We'll drive to the pier, I drop off Nancy and the luggage, then go to the car rental location, drop off the car, and take the free shuttle back to the pier. After we return, we do the same thing in reverse.
It's a little bit more of a hassle than taking a shuttle, but it can really be a cost saver, especially if you have more than two people going. Plus, you can do what you want when you want. For example, if you have time either before or after the cruise, you can always stop by Kennedy Space Center. It's an awesome place to visit and it's only a few miles out of the way.