We went to Orient Beach as part of an excursion. It is on the opposite of the island from Phillipsburg but I can't imagine it would cost more than $25 rt. Check the St. Martin tourist site, they might have fixed taxi rates.
A Bad Day At Sea [with power] Always Beats A Good Day At Work
Carnival: Glory 2004, Destiny 2008, Splendor 2009, Freedom 2011, Valor 2012, Dream 2013
Celebrity: Summit 2011
Princess: Ruby 2010, 2014, Caribbean 2013, Coral 2014
orient is not to be missed and if you are into nudity is the place to go.... just give yourself a couple of hours to get back to the ship... there is some construction work on one of the 2 roads in the island which creates terrible traffic.