Zipline excursion in St Maarten

[Sherimoe]

Hi there! I am going on the Disney Cruise in December. I want to do the ziplining excursion at Loterie Farms, but it isn't offered by our ship. I found one website where you can set it up for $84 per person, but have read other discussions where people quoted it anywhere from $37 - $55 per person. Does anyone have any ideas on where to go to get these cheaper prices? Thanks a million!