Cheap is a relative word when talking about the Bahamas. That being said, it's my experience that the least expensive airfares, are available by flying into Nassau. More flights, and more carriers servicing Nassau.
The mile is an English unit of length of linear measure equal to 5,280 feet, or 1,760 yards, and standardised as exactly 1,609.344 metres by international agreement in 1959.
Foot is an imperial and US customary length unit and defined as 0.3048 meters (30.48 centimeters or 12 inches). There are 5280 feet in a mile (US and UK), 6076 feet in a US nautical mile and 6080 feet in a UK nautical mile. The abbreviation is ft.