How to import products sold just by Amazon, not by other sellers

You can set the plugin to get only Amazon's prices (in "Configuration -> Amazon Config -> Import setup (tab) -> Prices setup" must be set to "Only Amazon") and then set the plugin to skip the import of products that have no price:

This way, only the Amazon's products should be imported.

 

OR you may use the Merchant ID filter. You can find the "Merchant Filter" in Advanced search on a specific category. It's named "Merchant ID".