With no link.
There's no way around it. The only way around it is if the user naturally finds/discovers the link to subscribe to a service via another method outside of the app itself. If the act of subscribing happened via clicking a link in the app, the commission must be paid.
In other words, no matter how the subscription/payment happened, if it originated from within the app (whether via a link to an external site or via apples payment system) you must pay a commision.
Either way it's mind boggling how the court didn't shut this disgraceful racketeering down
So with that in mind, it's more like paying for an apartment where you have to order your groceries and furniture over Apple's room service. When other businesses want dial-out functionality, Apple taxes them 27% of the transaction to enter the building. When you offer to walk outside and help accept the delivery, Apple locks the doors on you and tells you to buy a second apartment. Enough people have bought these apartments (and like them) that they want to change the bad door policy but keep the posh interior. Now Apple wants to play the victim despite claiming an ample 40% profit margin every time someone buys a room.
Would you be okay with Apple taking 30% from food ordering app companies when making orders through an Iphone? Because it's basically the exact same thing they're doing here.
In that case, the answer is not to force Apple to allow others to advertise lower prices in their store. But to force Apple to allow other app stores.
The ~30% was relatively reasonable when the App Store launched with most transactions being $0.99 one-time purchases, but isn’t very equitable for things like $15/mo subscriptions.