It charges again on its own until you stop it. Canceling usually keeps your access until the period you already paid for runs out, so cancel the moment you decide.
The drawing that proves the sentence above. It is the same card that is in the book.
Think of it as
a tap left running quietly in another room.
For example
A payment goes out for a thing you stopped using in March. Nobody asked you. It simply came round again.
This is one card out of 275.
The hundred words you meet most are free — the whole set, animated, in one file that works with no internet.
Volume 1 has all 275 in fifteen chapters, with Staying Safe the largest chapter on purpose.