Try http://www.zapperplans.com they offer free instructions for a simple zapper made from items available at Radio Shack. They also offer a ready made zapper for $10.00 including postage. I opted for the ready made one. I've been zapping for two weeks now. The only thing I've noticed so far is an improvement in the nail fungus on my big toes, but that is something important to me, I was too embarrassed to wear sandals this year with those ugly nails.
Go to the Zapper Forum and read posts by freelastchance. She loves the $10.00 zapper and has even posted pictures of it. I'm sure she will be glad to help you decide it this is for you.