Not sure if everyone knows about this but some of the apps in iOS offer a few different prices for the same plan. But it may force you to only sign up to the most expensive plan when trying to sign up. The good news is that you can change the plan via Apple Subscriptions.
For example, you can sign up to a free trial or monthly plan and then switch to a cheaper Annual or Monthly subscription instead of being forced to pay for most expensive yearly plan when signing up via the app.
An example of such app is Bussu: Language Learning if you look at the in-app purchases via App store, it has almost 4 different prices (2 different prices for premium plus and two different prices for premium) for annual subscription. But it may force you to pay the most expensive plan when trying to sign up for an annual plan via the app. So what you can do is to sign up the plan that offers 30 days free and then change your plan via Apple subscriptions to the cheapest one before paying the annual price.
I believe we did this for paramount. It’s certainly good to at least have a look.