hi caviiar,
Sorry you feel the way you do.
The source of the Safe Price feature is in Avast Online Security. At bottom of the window that will appear when you click the green AOS icon in your browser window will be a settings hyperlink called 'Settings'. Click that, and a settings options window will appear. Untick the Safe Price option, close it, and the price nag will not appear anymore.
If there are any other features that are bothersome, go to Programs and Features or equivalent, and right-click avast. Select 'change'. avast will appear to be installing again, but will first give you the custom install window where you can de-select features you do not want or will never use. Allow the program to finish, and when done, reboot.
You'll need to be in an administrative account to make changes you want to avast.
Additionally, if you are not running an ad-blocking program in the browsers you use, please consider doing so. A couple of good ones are AdBlock Plus and uBlock. Your webpages will load faster and you will be protected from malvertising (malicious advertisements). Not getting malvertisments will mean your risk of malicious infections and ransomware will be less than if you do not install and run an ad-blocker.
Choose only one ad-blocker.