Domestic air travel is cheap in the Philippines. Getting to Palawan from Cebu is only going to cost around 1400 to 1500 peso.
Departure tax at the Cebu airport on Mactan Island is 200 peso.
Keep in mind that it is a fair distance from town so allow enough time
to get there. There is a 45 minute cut off time for checking in before
the airline will let your seat go to those on standby.
They leave for Puerto Princesa 3 times a week from Cebu. Tues, Thurs, and Sat at 10:20am.
There is a major expansion at the airport in Puerto Princesa because
tourism is expected to boom in the coming years. Domestic and
international flights to Palawan are expected to to increase
dramatically.