The Free issue type allows you to setup issues that can be accessed for Free by subscribers and non-subscribers. This setting overrides any active subscriptions you have setup for your app and there is no need to setup any In App Purchases for this issue if the Free setting is enabled.
Click on your issue Cover
Select Edit Issue Settings from your issue menu.
In the next screen, scroll down to This Magazine is > then tick Free
Scroll down to Magazine Issue Type > then tick Standard.
Click Save Changes.
You are now ready to publish your issue!