You can get a trial and read for free for a month:
1. Tap "Buy subscription" in the app settings.
2. Tap "1 month - free" near the subscription type you'd like to purchase.
3. You'll see the warning that the subscription will be renewed automatically and the description of your subscription type.
4. Tap "Okay, let's go!".
5. Log into iTunes.
6. Tap "Continue".
7. Then there will be the warning that the subscription will be renewed automatically.
8. You can cancel the recurring subscription via App Store just after you got the trial. Click here for further information.