It's hard to justify an ongoing subscription for content that, for the most part, is already free with advertising. In the hope of convincing a few more people to pony up for the premium tiers of its digital media services, Google is offering a sweet deal to new subscribers: four months of free, no-strings-attached access to both Google Play Music Unlimited and YouTube Red (which are already bundled for paying customers). That's a $40 value at today's subscription price.