Air Asia just started their "Big Sale."

One way flights are as low as 4 USD; many are in the 40-60 USD range. I had good luck finding lower fares using the "view by month" feature.

Rules:
Booking Period : 22 June 2015 - 28 June 2015
Travel Period : 15 February 2016 - 31 August 2016

Link: http://www.airasia.com/ot/en/promotion/rr1780208.page