Hi, I was to the falls this past June on RCCL Voyager and have cruised to Jamaica a few times on my other cruises. I have always booked this excursion through the ship - it is always the cheapest one of them all. When you book through the ship it includes transportation, and the fee to get into the falls. I am sure you can do this cheaper on your own, however, I would recommend that if you are going to go out on your own try to find another couple or two to go with you. Go as a group. I have never had any problems in Jamaica, but like all Islands you need to be careful. When going to the falls make sure to bring water shoes with you. We always have a great time climbing the falls, it really is alot of fun.
Have a wonderful cruise, Sue