Those buttons are just a small bit of HTML form code. The button re-directs to their site. You can include some call back features on your site, such as a thank

Those buttons are just a small bit of HTML form code. The button re-directs to their site. You can include some call back features on your site, such as a thank you page. Using the buttons is the easiest way of integrating. If you are selling a number of products, then you will most likely need to eihter integrate an existing shopping cart or create your own.