Back in May of this year, Google unveiled its in-app subscription service, which allowed developers to easily add an auto-renewing subscription into their apps. Fast-forward to today, and Big G has added another new feature to the service: try-and-buy. Beginning now, developers can let users try a subscription for a a predefined amount of time without having to shell out the cash first. Here's how it'll work.
Once the service has been set up, the end user must "purchase" a subscription in the app. The process will complete as normal - the "sale" of $0.00 must be confirmed, and an email confirmation will be sent out, just as if an actual transaction was made. The user is free to reap the full benefits associated with the in-app subscription for the allotted amount of time designated by the developer. At the end of the trial period, the user's preferred payment method will be automatically charged the full subscription price.
As the trial comes to a close, however, the user will first be reminded via email that a charge will be applied if the sub isn't cancelled. If the user elects to cancel the sub, its use ends immediately. Nothing was paid upfront, therefore an extended use period isn't required. If the user chooses to continue the subscription, a charge is automatically applied through Google Wallet and a receipt is sent (those who currently take advantage of any subscription in the Play Store are already familiar with this).
For developers, the trial period can be set up in the Developer Console's subscription menu without the need to update the app's APK. It's worth noting that the trial period can be changed at any time, but it won't affect any user who has already "bought" the trial sub.
For more information on the trial period, go here.