Been running the 'or its free' for over 5 years, and never given a free job. I do get lots of worried clients who do not know who they are getting from yellow pages, so this 'fail safe', puts they mind at rest.
Saying that I live in Norfolk, and its quiet and relaxed. If I lived in one of the busier cities in the Uk, I would not use it as too many scammers in the larger places.