Definitely have a look at
X-Stream Cave Tubing as another option for cave tubing, we looked at Reggies too but X-Stream sounds like a much better trip.
The X-Stream excursion is only $60.00 per person and Reggies is $65.00, X-Stream picks you up right inside the terminal , with Reggie you have to walk out and look for him or something strange as he isn't allowed in the terminal(don't know why).
X-Stream also does an extra cave and only takes 15 in a group, and I really like the idea of a small group.
There are some great reviews for it posted on the carnival travel club board which is where I first read about it.