If you want to switch out your add to cart buttons on your Shopify store and link them to products on Amazon I am going to show you how.
Install my Shopify app Outbuttons to your Shopify store. This product allow you to link the products you chose to an external website. It can be Amazon products or products on any site of your choosing. Best of all you get a 3 day free trial to play with it.
Once the app is installed go to the Outbuttons app in your store. Any products that you want to link to Amazon have to be set to on. They also need a link in the external URL and your desired button text.
Save and check the pages of the items you linked to Amazon to make sure they are working properly.
Check back on occasion to view your stats and see how many clicks your products buttons are getting.
It is a pretty simple process that can be accomplished in just a few minutes.