Originally Posted by
PTravel
Definitely buy a phone as described here. However, the OP should post in both the China and HK forums. Most SIM cards purchased in China won't work in Hong Kong and vice versa, i.e. the OP may need to buy one in each city.
Not true, there are now dual number prepaid sim cards that have both an HK and China number. However they are mainly sold in Hong Kong.