It backfired when an examiner told a potential client on the phone "I charge $600. If you pay any less, it won't be a real test". This was the first call the potential client had made about polygraph.
Note-- this first examiner has a history of bad-mouthing other examiners.
That potential client then called many other examiners in the same area. ALL were a lower cost, and most were far more experienced than the $600 charger. And as the other examiners all told the potential client, "The computer polygraph doesn't know how much you paid", potential client realized she had been lied to by her first contact.
Potential client then went to a more experienced examiner, paid far less, and was very pleased with the results.
In any business, potential clients spot the desperation when one professional badmouths another.