Ricky did it through Riu it was 1000 for a 10 person boat. Depending on how many are going you are better to do it when you get there. There are tons of venders at the Marina and along the beach. If you need a 10+ person boat it may be a bit harder and may want to reserve before hand. To be honest Ricky found it really boaring. Its a long hot day if you have no bites. Alot of them got sea sick b/c the water is choppy. The day of the wedding him and a couple GM just went regular fishing in a small boat around the arch and they caught a shark and about 10 huge fish. Needless to say it was waaayyy cheaper and they had so much fun! Hope this helps!
Sarah