Hong Kong Express Airways have ”Buy 1 Get 1 Free” on 1 November, 2016.
As for this sale, one becomes free when you make a reservation for two people.
・The Japanese route
Tokyo(Haneda)⇔Hong Kong
Tokyo(Narita)⇔Hong Kong
Osaka(Kansai)⇔Hong Kong
Nagoya(Chubu)⇔Hong Kong
Hiroshima⇔Hong Kong
Takamatsu⇔Hong Kong
Fukuoka⇔Hong Kong
Kagoshima⇔Hong Kong
Okinawa(Ishigaki)⇔Hong Kong
Sale period: 1 Nov, 2016 – 3 Nov, 2016
Travel period: 15 Nov, 2016 – 25 Mar, 2017
A per person fare is almost one-way around 5,000 JPY.