According to a blog post, US users "who do not yet have a Prime membership or a subscription to Amazon Music Unlimited" (yet, Amazon says) can now listen to select playlists and stations for free.
It's not likely you'll want to use Amazon Music's free tier over Spotify as your default service, given that it offers a very limited supply of music (roughly 2 million songs versus Spotify's estimated 35 million).
Amazon on Thursday announced that everyone with an Alexa-enabled device can now listen to music for free. Amazon is now the third largest music streaming service in the world, right behind Spotify and Apple Music. The company's announcement follows a report earlier this week that claimed Amazon was preparing to launch a free ad-supported music service to compete with Spotify's free tier and similar services.
Listeners can choose the genre of music, but can't create specific playlists. Amazon Music Unlimited, which starts at $7.99 a month, offers over 50 million songs. The free tier is ad-supported, as Billboard's report suggested earlier this week, but it allows anyone with an Echo to play music without paying a subscription fee (though, as you would expect, there are some restrictions).
With its free, ad-supported music streaming service, Amazon is probably looking to convert Alexa users into paid customers.