The Aeropost.com app lets you buy almost anything from Amazon or eBay, and pays for it directly on the app, which includes shipping and taxes.
In the Store section, you can access online stores from retailers like Amazon or eBay. From there you will see the final price of any product, including item costs, shipping and taxes in your country.
You can add the products of your choice to your shopping cart and pay for them directly from within the app.