I'M NEW TO ZAPPERS. I BELIEVE THAT THEY DO WHAT THEY CLAIM. BUT WHY ARE SOME $10.00 LIKE AT WWW.ZAPPERPLANS.COM AND OTHER PLACES THEY SELL FOR HUNDREDS OF DOLLARS??? IS THERE A QUALITY DIFFERENCE BETWEEN ONE FOR $10 OR ONE FOR $700??? CAN YOU TRUST EVERY SITE SELLING ZAPPERS? THANKS FOR SOME INFO.