For airfare, if you can make it to NYC pretty cheaply, you can go on Jet Blue (a great airline) to San Juan for $200 round trip. Then $200 or less gets you round-trip to Sint Maarten. Or you can set up fare-watchers on Travelocity, follow bestfares.com (a $70 membership which you can sometimes save on the ticket price alone), or whatever. Connecting through Neward with Continental, Charlotte or Philly with US Airways, and JFK, San Juan or Miami direct to Sint Maarten. Also, I think Delta flies in direct, too, from Atlanta.

Lotsa decent fares to be found, if you have the money to buy on the spur of the moment when they drop for a few hours. Just keep checking them. If your dates are somewhat flexible, that helps, too.