Well,
see if you are talking the real FREE avs's.. then surfer doesnt get the suprise that their card is NOW being charged $39.99. On the real free, there is a legitimate 3 day $0.00 trial.
There are plenty of fake free ones that have fooled me, up until you enter your card info etc.. then you see the whopping free charge : )
Most of the real free avs's use ccbill. We use ccbill with jettis backup. So the rest is just the join process and the presentation of the join form.
But there is also going to be some surfers that are going to come to your site and already have certain avs passes or be able to easily get them. Were if you are new, they are a lil harder to find
Chris