Thank you for your tips, I have just booked a return ticket for my helper for only $160 per flight, the return ticket including tax is HK$677.17 only, it is unbelievable. We checked a few days ago(also at Cebu's website), the same flights costed about HK$1,200!!
Yes, it's really lucky that I booked the airticket for my maid to have her trip in early Aug at the lowest price. It costs only ~$1000 for return tickets to/from Manila plus one return ticket for domestic flight.
It's Cebu's promotion period for int'l flight at P999 (philippines $) and domestic flight at P1.
PS. the sale period for int'l flight has expired yesterday. I just check the website and the return ticket will be now $280 more. Actually still attractive but not the lowest!!