To set the stage, my wife and I are in our young 30's, cruise on a budget, and we were on the Liberty a little over a year ago and love this class of ship. We really love Royal Caribbean over other cruise lines as well.
Taxis to/from FLL
The taxi for 2 people from Ft. Lauderdale to the port was $12.50 before tip, taxi from the port to FLL was $14.90 before tip. Out of curiosity, I inquired with the RCCL transfer folks at the airport and they said the transfer cost was $15.90/person! Why wait for a bus to fill up that costs literally twice as much as a taxi? Of course, we took a taxi both ways.