Please note that after the trial period is over, you are free to continue using the app. The main limitation is that the sleep tracking functionality will be disabled for sleeps starting on Mon, Wed, Fri and Sat. But you can still track the other days and use all the alarm related features such as CAPTCHA, Bedtime… every day. Also after the trial you may be seeing advertisements in the app. With the Unlock you also get access to more nature sound ringtones and lullabies. If you purchase the unlock you will get all your data even form those days, when the tracking was restricted in the free app. If you decide to purchase the full version we would of course very much appreciate that as it helps us to constantly improve the application.
This is a companion discussion topic for the original entry at https://docs.sleep.urbandroid.org/faqs/purchase_trial_expires.html