Those of you who have a chromecast, it shouldn't matter when you purchased, are eligible for 90 days of free All Access music from Google Play. You can't be a current subscriber and you'll have to cancel at the end of three months to avoid being billed but it's a pretty good deal that you don't have to do anything extra for. It's a good music streaming service that also allows you to download music and works Android/iOS.

https://support.google.com/chromecast/answer/6008760 

*You will have to be on the same network as your chromecast to be able to verify the offer so I haven't been able to test it out yet.