Avast usually has pop-ups about getting rid of useless programs or general advisements about internet security. Recently one pop-up appeared mentioning wi-fi security and the Avast Secure line VPN. I clicked on it to read more about it and it took me to a website called testgarage.com and it mentioned purchasing Avast Secureline VPN. Is this from Avast or is this some kind of virus or hack? The box looked just like Avast’s pop-up boxes in the lower right corner.
Google … Avast vpn … and see what you find. 
For more info also see FAQ section found at www.avast.com
Also try forum search