check this https://payments.amazon.com/sdui/sdui/helpTab/Amazon-Flexible-Payments-Service/Getting-Paid/Adding-Funds-to-Your-Account-Balance
Amazon Payments is mostly for US account holders. I think you can shop on other retailers without re-entering your shipping address and credit card number. If you join Amazon Mechanical Turk and complete small tasks over there, then those payments will be shown in Amazon Payments.