Re: They say this is the best, but its ££$$££!

The Zapper circuit is public domain. The Zappicator is just one loudspeaker with one wire connected. You can do it yourself, and that's for me the biggest advantage of this "technology". Both are published in Clark's books - the Zapper in every one, the zappicator not, but you can still find it in Internet:
http://www.escalatorhi.com/JimDabblingH/asgzapperkit.html
Tweet