All costs are per person basis :
Return airfare (KL-Miri) : RM250 approx
Return airfare (Miri-Mulu/Limbang-Miri) : RM270.80
Mulu/Limbang : Airport transfer from Mulu airport to Park HQ (RM7).
Mulu National Park HQ : RM464
Covers the following: 2 nights hostel accommodation at Park HQ. Inclusive of 2 breakfast only, Racer Cave, Deer and Langs Cave, Wind and Clearwater Cave, Longboat one way to Kuala Litut, 2 nights at Camp 5, guides for Pinnacles and Headhunters' Trail, boat to long house and Limbang and park entry fee.
Lunch & dinner is not included. If you don't do the Pinnacles and Headhunters trail of course this will be much cheaper or you can also opt to stay at the more upmarket Royal Mulu Resort (I think RM88++ per person per night).
Certain caves you have the option of taking a boat instead of walking, which of course will cost extra.
Longhouse : RM41
Covers the following: Dinner and B'fast at longhouse, 1 night accommodation at local longhouse.