For 6 of us, it cost half a new roof. We wanted to get all the kids together for a possibly last time. Any farther down the road, and there will a lot more to go, since the younger two are still single.
It was a great trip. We chartered a 55 foot catamaran with a married couple as crew. They did everything for us, food and drinks were all-inclusive, and it included several scuba dives for the certified ones. She was a master chef and he was winning bar and dive-master.
I'm still recovering. :) It took 2 days to get your sea legs on very calm water, and another two days when you came back, to stop the floor from swaying. I snorkelled on a lot of reefs and saw many pretty fish.
We'd love to do it again, but we have to build up the war-chest. :)