Google developers now have the option period offers a 'try before you buy' in their Android Market application. Actually, Google already launched the subscription application in May, but until now the developers have not been able to try out a subscription before you sure you want to decide.
Now, they can use the Developer Console to set the number of days (7 or more) that enable content subscriptions tries, before the charge is valid. This period can be changed at any time, so they do not need to return the application to the market.
Any developer can set the initial probationary period automatically and will automatically convert to a full subscription in one period.
Following is Google explained about terms of probation:
To be able to take advantage of the free trial, users have to 'buy' a full subscription through In-app Billing standards, provide a valid form of payment for use in billing and completing the purchase transaction. However, users can not be charged since enrolled in a free trial. Instead, Google Play recorded transaction of $ 0.00 and a subscription is marked as 'purchased during the probationary period or until cancellation.' Once the transaction is completed, Google Play will notify users via email that they have purchased a subscription that includes a free trial period, and inform the charge is $ 0.00.
origin source by Android Developer, image from The Next Web