Google Play Music used to offer free albums every few weeks. It looked like a win-win for everyone: people could get some free tunes, and Play Music would attract people who might not have used the service otherwise. Perhaps Google didn't feel that it was worth doing anymore, as we hadn't seen anything of the sort for over two years. But now, albums from Ariana Grande and The Beach Boys are just $0 from Play Music.
The albums are Ariana Grande's "My Everything," which contains 12 songs, and The Beach Boys' "ICON," which has 11 songs. Both can be added to your Play Music library for absolutely free; just hit the "Free" button to do so.
Only people in the US seem to be able to take advantage of this offer; people in Canada, the UK, India, Australia, the Philippines, Brazil, Denmark, Belgium, Taiwan, etc. have all reported that they were unable to get it. So for now, we'll err on the side of caution and say this is US-only.