Hello Nick,
I apologize for the inconvenience. You can turn off those campaigns notifications permanently in AVG interface. Please open AVG Internet security > Menu > Settings > General > popup > uncheck "show popup offers for other AVG Products" > Restart your AVG Program and check the status.
If the issue persists, please provide the screenshot [http://support.avg.com/SupportArticleView?urlname=How-to-create-a-screenshot] of the popup message to check and assist further.
Nick, If applicable… For your info, just in case that you are unaware, you can post the screenshot here in your topic. Click on 'Answer' & then click on the 'Image' [mountain symbol] & follow the instructions.
AVG Guru