expired Perth to Kota Kinabalu, Malaysia $154 Return via Malaysia Airlines (Non-Stop & Full Service) via Aunt Betty
Malaysia Airlines is offering return flights from Perth to Kota Kinabalu, Malaysia for $192 or $154 with coupon code. Fares include seats selection, bags and meals. Dates appear to be from May to November. Pretty cheap for full service international flights.
Don't know much about Kota Kinabalu but Lonely Planet has a guide. Looks nice. 3-star hotel averaging $46, 5-star averaging $201.
Update: SCF sent out another email Port Hedland (PHE) to Kota Kinabalu $540 return. Good if you live in Port Hedland area.
Excellent (and rare) fares from Port Hedland to Malaysia. It's possible to drop the price even further by booking an open-jaw ticket returning from Kuala Lumpur ($510). Additional return flights are available from Johor Bahru, Penang or Langawi for $545, if you prefer.
All flights have a stop in Perth, and many have an additional stop in Kuala Lumpur on the return journey. No bag fees.