Please consider augmenting your payment model: I would definitely purchase this software but NEVER on a subscription basis as there is no way for me to easily cancel the charging process at the end of a year. I’d pay the full $12 (or even more) if you contacted me at the end of a year to re-up.
Maybe this will help:
Turn off Auto Renewal :
https://www.avast.com/faq.php?article=AVKB24#idt_0100
Scroll down and you’ll see Cleverbridge or go here:
https://support.cleverbridge.com/hc/en-us/articles/204345588-How-do-I-cancel-my-subscription-
Access help on this topic within the Avast User Interface:
https://forum.avast.com/index.php?topic=165749.msg1181311#msg1181311
You can also look at/change the auto-renewal yourself here: https://www.avast.com/find-order