Bus is the S64 to Tung chung. Cost is $3.50HKD and then the MTR into town, about $8.00 I think. Tourist octopus card is the best idea, makes it a whole lot easier to get around and most of the 7-11's take it to buy things with as well.....like a beer to get you home
Have fun mate
Nosey
Edited to the S64 as per below, sorry for the tiki tour!!