You don't need a jailbreak for this, but what you do need is a second apple id where you select a country as the location that the app has in the store. this means you can select any Mcdonalds in Germany and use their address when creating the appleid.

You need an iTunes account in a country where the Amazon app is available, e.g. USA or Germany - easy to do without a US credit card, no jailbreak needed.