I wish I could set up "Sign in with Apple" on a blog without paying $99/yr for a developer license.
Is it a benefit to you? If it is why should you not pay for that benefit?
Nothing is free.
Plus, it's not for the dev, it's for the users of the website.
https://www.apple.com/legal/privacy/data/en/sign-in-with-app...
>When you use Sign in with Apple on Safari, Apple sees when you sign in to a website so that Apple can authenticate your sign in, but Apple does not retain a history of what websites you sign in to or when you use Sign in with Apple.
No leaked email address, no need for anyone to store password, people using iCloud instead of Gmail.
What they're asking, for it to cost zero, sounds perfectly reasonable here.