What if I don’t want to add a card

Apple does not charge users without consent, any charge that is applied to your payment method needs to have been started and approved by you through multiple steps. Further, there has been no knowledge of a hack on Apple's iTunes store systems since its inception really.

Any charges you received, were there because of something you did.

With that said, an Apple ID requires a valid and verifiable payment method. You cannot use it without one.

Once and added and correctly verified, however, it can be removed, and should not ask for it again.

You can then use iTunes gift cards as suggested by Idris above.

If you're asking about how to fund purchases from the iTunes/App Store, you could buy an iTunes gift card and add that.