Spirit Airlines offers roundtrip flights to the Caribbean from select cities in the U.S. with prices starting at $183.18, as provided by ShermansTravel. (Click on "Spirit.com" in the main paragraph to see this sale; all taxes are included.) That's the lowest current rate we could find for select routes by $10. This price is valid on flights departing from Fort Lauderdale, FL, (FLL) to San Juan, Puerto Rico, (SJU) on December 4 with return on December 11. Book this travel deal by November 30 for travel through February 2015. Click here to see more routes.