Marketplace
Similar to the Spotify deal, I noticed that Google Play music now has 2 months free (versus the normal 30 days).
You'll need to have a Google account and CC details - just don't forget to cancel the subscription close to the 2 months - otherwise it will revert back to charging you $11.99/month
Legals are here
Don't forget you have 50,000 songs cloud storage too! Perfect for filling in gaps in their library.
*edit: grammar