The $18 per resume there is after human screening removed the bad resumes. Pleasepoachme charges $10 per match - and as far as I can see all they do is a text match on the requirements.
In the post you linked to, he had to review 39 LinkedIn resumes to get 11 qualified candidates. Based on the Pleasepoachme rates, looking at 40 resumes would be $200. Assuming 11 candidates were found, that is $18 per qualified candidate.