when you want to creat new In-App Purchases that have "only free subscription" and no each other option
you can follow next step...
login your iTunes Connect Account and click "Contracts,Tax,and Banking".
Master Agreements, Request and Fill all about your information then finish it.
go to iTunes Connect homepage and click "Manage Your Apps"
click "Manage In-App Purchases"
click Create New
then that will show you
Consumable,Non-Consumable,Auto-Renewable Subscriptions,Free Subscription,Non-Renewing Subscription.
This Just my note...