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.
There are 5280 feet in a mile, because one mile is defined as 8 furlongs and 1 furlong is 660 feet, that makes 8 * 660 ft = 5280 feet in a mile. For example, to find out how many feet there are in a mile and a half, multiply the mile value by the conversion factor, that makes 1.5 mile * 5280 = 7920 feet in a mile and a half. Mile is an imperial and US customary length unit and equals to 5280 feet, 1760 yards, 63360 inches, 1.60934 kilometers and 1609.34 meters.