A: It depends on which airline and which period, right. Give you some idea...
About the price....
Cathy Pacific >> Phil airline >> Cepu Pacific
more expensive ........................Cheaper
About the travel agency...
Hong Thai; WingOn, BOC travel, etc.
Give you one example....
Month: Apr (not peak season)
Airline: Cepu Pacific
Hong Kong --> Manila
Price: Round trip --> HK$1350 +193 Tax
One way --> HK$7550 + Tax
Travel agency: BOC travel