Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Singapore to Barbados as you normally would.
If you book a flight to Barbados from Singapore, you will be flying from Changi, which is the city’s only airport. Singapore Changi (SIN) is located 16.9 km from the centre of Singapore.
This is defined as Singapore Changi Airport (SIN) and Bridgetown Grantley Adams Intl Airport (BGI). Codes like Bridgetown Grantley Adams Intl Airport are often used to just call airports uniquely.