I'm not a nail technician I'm a holistic therapist - massage, reflexology, etc - but I come across the same problem and my impression is it's one of two things usually. New starters in the business and the couldn't care less about the client as long as they make some quick money brigade. The second I don't give time or thought to, they are not worth it. The first think if they charge properly they won't get a start with clients or they don't feel confident in their abilities (which we all remember I'm sure!) straight away, however good they may actually be, so they feel unworthy of charging correctly. My approach with any therapists that I come across is to try to guide them and explain industry standards, insurance, etc, and stress how important it is for their own protection in the long run if anything should go wrong, God forbid. My approach with current or potential clients who tell me there's someone cheaper is to tell them to go try by all means, it's their choice who they see. However, I also tell them they only have one body and it's costly (if even possible) to get mistakes put right so I advise them:
"Before you ask what appointments are available, ask the person who is going to provide your treatment what regulatory body they are registered with and what insurance they have to do that type of work."
"Look around their workspace. Doesn't matter if they are doing it in a kitchen or a cupboard or a rented therapy room, is it clean? Do their tools, hands, etc, look clean and well maintained? If they were going to serve you food, would you eat it after they had handled it?"
That's usually enough to make clients think twice, but if they go ahead and I manage to get feedback:
"Did you get the treatment and experience they promised you they would?"
"Did they question you generally on health issues, current illnesses and any contraindications to the treatment?"
"Did they advise you on aftercare and how to contact them if there is a problem?"
"Were you satisfied?"
At the end of the day, clients will choose their own therapist, for good or bad.