Personally the nagging promotions/aka ads don't bother me that much.
I know a VPN would hide my ass (an interesting name of just one such product), but hide me from what, I don't visit sites that I would want to hide my having accessed them. I get a laugh out of many of these promotions as they are dumb by nature (they don't dig deep into your system) and just throw up this infor'mercial style promotion (that is tantamount on spying on the user). Such as throwing up the VPN promotion even when the user is already using a 3rd party VPN (just not Avast's VPN).
Others I just go so bloody what, I look after my systems security/backup, etc. etc. and and just ignore them. Obviously it is working and people are taking up the offer or they wouldn't continue.
I just wish they would become more intelligent in the delivery if I haven't taken them up in 17 years of using Avast Free (which meets my needs) to dial down the volume/frequency of such promotions.
I too used Agnitum Outpost Firewall Pro 9.3 (lifetime license) for some considerable time until I effectively retired my XP Pro system.