depends on the type of job agents you are comfortable with
lor.
Some agencies are paid by their client (which is your employer
which u sign the letter of appointment with)
some agencies take commission from your salary.
others I don't know.
But one thing for sure is that if the job is recommended by a job
agency, you have to sign a agreement with the agent that you must
not resign or tender resignation within 2 months of signing the
letter of appointment with their client. If not you have to pay
them full amount of one month of your appointed salary.
One thing good from a personal point of view about them is that
they will try to recommend your salary as high as possible
.