Amazon to sell $10 cards for $5 to lure customers - Yahoo! News
Here is how it works. Go to AmazonLocal.com. Its Amazon's new daily deal site. Pick a random city (I picked LA). Link it to your Amazon.com account. First deal of the day is $10 amazon credit for $5.
Works with a HK credit card, just tried it.
Do read the T&C's though.
I have two Amazon accounts with different credit cards. Was able to apply two vouchers to one account though (but had to buy through the separate accounts).