And Apple likes to pretend that there are no better payment options. I would prefer to subscribe via PayPal, because it's easier to cancel via them than via Apple's iTunes corpse.
Settings -> AppleID -> Subscriptions?
It’s on your phone? You don’t have to use iTunes at all? I wouldn’t have even thought to use iTunes? Unsubscribing is the easiest thing in the world - much easier than PayPal. It’s right there in the Settings app.