Magento provides configuration for your pricing scope to be set to global or website. If pricing is set to global scope, there will be a single price source for all websites. If pricing is set to website scope, websites can vary their pricing across and also have a fallback default pricing value. To set your price scope, see Magento Price configuration.
If you change your catalog price scope from global to website, all price type attributes will also change to website scope. For more information, see Adding Websites.
When a website price is selected, there are two price sources: the website price and the default (fall back) price. For the Amazon integration, based on your Listing Rules, you can map products from multiple websites into a single Amazon marketplace. However, this introduces the issue of which price should be published if the product exists on multiple websites with differing prices.