I highly recommend Godfrey's tour. He will pick you up at the ship at either 9:00, 10:00 or 11:00 (your choice)take you downtown for shopping, then do a two hour tour of the island. You then choose a beach (Maggens, Coki or Saphire) to go to for two hours if you wish or he will bring you back to the ship.
All of this for $20.
Here's his website which includes his email address.
We have gone on his tour twice.