Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Denpasar to Bulgaria as you normally would.
Denpasar Bali Ngurah Rai (DPS), located 9.6 km from the city centre, is the airport you fly out of when you book flights from Denpasar to Bulgaria.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Denpasar Bali Ngurah Rai Airport to Sofia Airport flight would often be abbreviated as a DPS to SOF flight. Ready for more IATA code knowledge? These are related airports for your current travel destination: Varna Airport (VAR), Bourgas Airport (BOJ), Plovdiv Airport (PDV).