The iOS Google Play Music app is free to download, but to make the most of it, you'll need an All Access membership, which will cost you 10 bucks a month.
Earlier this year, Google launched the Android version of its Play Music app, which is intended to compete with stream-on-demand services such as Spotify and Rdio. Today, the Google Play Music software finally lands in the iOS ecosystem, in the form of an app customized for the iPhone.
It's free to download the app, and if you've already purchased tunes from Google Play – or uploaded tracks from your own collection – it'll be free to listen to those songs, too. But to make the most of the software, you'll need an All Access membership, which will set you back 10 bucks a month (on par with similar offerings from streaming music competitors).