With the latest version of the Amazon Music app, Amazon Music subscribers who own a vehicle equipped with CarPlay can access their music directly through the CarPlay interface when an iPhone is connected to the car.
Amazon Music is available to Amazon Prime subscribers, with two million songs, playlists, and stations included in a membership.
Separate Amazon Music Unlimited subscriptions are also available for on-demand listening to "tens of millions" of songs, with pricing starting at $7.99 for Prime members ($9.99 without a Prime subscription). A lower-cost Echo-only plan is also available for $3.99 per month.
Amazon Music can be downloaded from the App Store for free. [Direct Link]