I know this post is a few months old, and I am not sure if this has been purposefully changed or not, but I do know that there IS a premium side to the Anti-Theft app. However, it does seem to be for free?
When I went to the website it had the interesting features, like the ability to hear the audio, grayed out. So I started to do a little digging. There is a premium option in the phone app. It will pop up letting you know all the great features, but it doesn't mention a price. I clicked on it to see if it would pull up a price... and BAM... I had the premium version. Apparently until November of 1909... which I think it will take a long time to invent a time machine so we should be good.
Anyhow, I've checked all my financial accounts, and nothing seems amiss. My avast account does list the audio and camera features now!
Hope this helps!