Well, it seems that it is cheaper from Philippine to Hong Kong, but it costs you much more from Hong Kong to Tianjin. If possible, it is suggested that you fly into Beijing and then transfer to Tianjin quickly by express train.

There is shuttle bus you could take just outside of the Terminal #3 of Beijing International Airport directly to Tianjin City. Only 70RMB. So you don't transfer from the airport to South Railway Station of Beijing to catch up the high speed express train.It save a lots, especially the time.