American Airlines has round-trip flights from Denver (DEN) to Sint Maarten (SXM) for $371 with a connection. Flights August, September, January, February, and April. No Saturday departures. Departures are late night “Red-Eye” flights.
Priceline has “Express Deals” for $349. These are likely to be late-night “Red-Eye” flights also. With “Express Deals” the airline and exact flight are hidden until after purchase and those purchases are final. There is no 24-hour free cancellation for “Express Deals”. The flight is guaranteed to be on a major airline. Be sure to select the deal with 0 to 1 stops and a layover less than 4-hours.
Click for more details and booking links Cheap Flights: Denver to Sint Maarten $349-$371 r/t [Aug-Sep, Jan-Apr] (Late-night Red-Eye) – American Airlines / Priceline Express