I have recently found a flat in Kennedy Town for $44 US per night. That is the best price going, next to rent-a-room, or some of the hostels showing up on hotelscombined's Hong Kong listing. Check it out on my page. It seems to be a decent 300 sq. ft and even with a sea view. I know, sea view doesn't matter to all you Hong Kongers but for this middle America guy, sea view is King!
Bill is a Midwestern American whose wife is from Hong Kong. He has three daughters and the entire family visits Hong Kong almost every year.