Amazon has a page for Android app deals.
Seems like you can only "buy" free apps if you've got a credit card from a supported country, which is very limited nowadays.
Two questions here:
Did I do my research right? Is there any way to "purchase" those Amazon free app deals from an unsupported country? On a likely unrelated question, maybe can I get a credit card from one of the supported countries without residing there?
If you bother to answer, why do they even set up this restriction for free apps, anyways? Apple, for one, doesn't do this. You can get a free account there and get free apps from anywhere.