You can get a reasonable tour of the island from mini bus drivers just outside the port - There is a bar to the right when you come out of the port - maybe half a block down - up a flight of stairs - It is called Local Bar - free wifi and very reasonable cold beer. Nice staff.
The Island has quite a bit of damage from Hurricane Sandy - the lush greenery is brown, I guess from sea water washing over it - the beach is not quite as big as it used to be. The water is still nice to swim in though
If you take this tour be sure to sit on the side of the boat that the driver is on because he seems to spot the most wildlife and the boat is turned to that side most of the time.
We were lucky enough to see sloths, howler monkeys and lots of birds. After the boat ride we had about 10 minutes to shop, eat fruit and drink beer. Then we went to see a banana plantation. Our guide was obviously very proud of his country and provided great information.
For shopping, there is quite a large shopping area right at the port - a market with free wifi, cheap beer and you can have a massage or manicure or pedicure. The shopping is more reasonable than we found after the boat ride.