I was trying out a bunch of weather apps (why is is so hard for a simple concise app with a radar without a bunch of needless fluff/wasted space) and 1 of them automatically turned into $99/year after 3 or 7 days (I forget).
The app didn't even work and would almost _always_ have the time wrong making the weather HUD also inaccurate. I tried to tell apple about this and they refused a refund. Thankfully my credit card company allowed a chargeback
I can only blame myself for forgetting these things, but it would be nice for a prompt prior to the subscription starting next time you use the app.
You can tell people what it'll cost and ask for a card, or, you can say it is free and not ask up front (you can ask later if you want but having not given you a card for the free trial if the customer has lost interest they're not going to give you one later)
The problem is a huge percentage of users assume deleting the app will also stop their subscription, but it does not.
"You have a subscription for this app's services through Apple Pay. Do you want to unsubscribe?"
They could even say something like
"You have a subscription for this app's services through Apple Pay. Do you want to unsubscribe? Note that this app is still installed on your iPad" (assuming you deleted it from your iphone)
As a tangent I notice that while Apple's hardware and OS are best in class their support infrastructure is arguably close to worst in class. Every time I have to deal with their support and order systems (apple.com) I run into issues that make it almost seem like they're still doing everything on paper and that none of their systems are connected.
I've never seen a simpler and more straightforward billing UX as Apple's.
Settings -> <Name> -> Subscriptions
Settings -> iTunes & App Store -> tap on your Apple ID at the top of the screen -> tap on view Apple ID -> scroll to subscriptions and tap on that
It’s not obvious or intuitive in my opinion.
You can also like the parent poster said, use App Store -> Profile Picture -> Tap Apple ID -> Subscriptions.
I don't like how it doesn't show the purchase method on the TouchID screen - it's fine if you are using it a lot, but if you only use it infrequently, it's annoying to not know which payment method it is using.