Questions

The ones that actually get asked

Can I cancel without signing in?: Yes, through the dedicated cancel page. From inside the account it is two clicks.
What happens to the period I paid for?: It stays valid to its end, and then the renewal stops.
Does my account become a plan without charge?: No, because no such plan exists. When the period ends, so does access to downloads.
Why do I not recognise the charge on my statement?: Because it carries the payment provider's name rather than the site's.
Can I subscribe again later?: Yes, but the intro week is offered once per customer.
Do I pay from the start?: No. Running the tool needs no account; paying is about the download: 7 days at an intro price, then monthly.