AVG is a popular Antivirus vendor that offers a free version of it's product at http://free.avg.com/. Rather than getting money by bundling this free spammer with pay-per-install adware, scammers have created websites to sell (free) AVG!
The three fake sites redirect the users to a payment form. The first page gathers names and e-mail addresses. Even if the user decides not to pay, the scammer can still spam the user, or resell their e-mail address. This is no small profit!
Then, the user is required to pay for the software. The payment is actually not for AVG itself, but for a monthly maintenance fee:
|Monthly "maintenance" fee|
The real Free AVG antivirus product is completely free of course, including access to the antivirus definition file updates.
A search for "free avg" shows a lot of other spam sites, most of which are fortunately harmless.
As always, users should make sure they download their software from the official site. AVG flagged these three sites, but Google Safe Browsing and Internet Explorer did not. Of course, people looking for Free AVG clearly don't have AVG installed yet.