Ive priced loads of jobs that were just check prices and they allready had someone to do it. Its just part of being self employed we do it ourselves, we shop around.
Its pretty simple to spot really, I have like a script of things to say to new customers (a bit like a sales pitch but not really) it's designed to make them feel confident in me. Its a questions and answers thing but when you say the price thats when they lose interest as thats the only thing they wanted.