The question bank is free. Pro adds the answers.

Every signed-in account gets the whole question bank — every subject, every topic, every paper and session, plus all the TI-Nspire and Casio calculator guides. That part does not expire and costs nothing.

Pro adds markschemes and examiner reports: on screen next to the question, and included when you print an exam. One payment for a fixed period — nothing renews by itself.