The most affordable place to stay on your visit to Hong Kong is not Hong Kong.
The trip from Hong Kong to Macao takes only one hour and an economy class ticket costs only HK130.00 (US$18). I caught my jet boat above Central station (on subway line) on Hong Kong Island. Relative to Hong Kong, accommodations in Macao are inexpensive (expect to pay two thirds the price for similar value); the old town has plenty of budget options. And for those who come to test their luck, new casino resorts are springing up like weeds.
Photo: Looking back at Hong Kong on route to Macao (Macau). I took it from the window of my hydroplane.