Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Tacloban City to Sri Lanka as you normally would.
For a flight from Tacloban City to Sri Lanka, you will be flying from D.Z. Romualdez. Tacloban City D.Z. Romualdez (TAC) is just 3.1 km from the center of the city.