You export to either html5 web, or apk. Go over to developer.amazon.com and sign up to use the appstore.
Once you're signed up look for the button that says "add new app".
There is no Construct plug to use the payments api that I know of, other than the one that doesn't work in C2.
There was the premium thing that paid by time spent in app, but I think they dropped that, so outright the only way to monetize is by selling the game through the store.