If Hong Kong offers unlocked Iphone 5 you can use any GSM networks with it. But the cost of the Iphone 5 in Hong Kong is 16GB HK$ 5,588, 32GB HK$ 6,388 , 64GB HK$ $7,188. In order to save money i would suggest you to get locked Iphone 5 at any of the websites like official apple store, eBay, amazon, jobong etc... and get it unlocked at low cost. Because the price of iPhone 5 Locked is 16 GB – $199, 32 GB – $299, 64 GB – $399. Use remote unlocking service to unlock your Iphone 5 at the site [Unlock-Zone.com] ,and unlock it yourself using unlocking instructions which is given in the site itself.