"Google Play Music All Access is a new monthly music subscription service that lets you listen to millions of songs across your devices. You can create a radio station from any song or artist you love, browse recommendations from our expert music team or explore by genre. (...) It's $9.99 a month, and you can try it free for the first month. Or better yet, start your trial by June 30 and you'll pay only $7.99 a month."
Instead of buying music, you can listen to the entire Google Play catalog. It's not free like Pandora, but you can listen to any song you like, as long as it's available.