I know one of these consultants, she's a good friend, she makes $500k/yr; she'll get your kid anywhere and she has a long list of very wealthy clients. I do not know how much she charges though; but her salary should give you some rough ideas.
I'm guessing she is not unethical though and cant get any kid into any school. That said if she knows what she is doing it could easily seem like she can to a casual observer.