Discussion on paid agency: is it necessary?

Hi there! I am new to WSO. I have a few questions and I really want to hear your opinions!

Some paid agencies offer programs to help college students break into IB. They have systematic training and mentorship on CV & cover letter editing, access to OTs in advance, tutoring in HireVue, training in Behavioral and Technical interviews, etc.

The fees of most programs like this are around $5000. 

I am hesitating to join one of these programs. I have done several internships in PE and IB but in mainland China. I have no experience in BB recruitment. I networked with alumni and attended info sessions organized by the firms. But somehow I feel maybe I lack something that a successful IB candidate requires and maybe it's a good idea if I have someone who has gone through the recruitment journey successfully.

What do you guys think of such agencies? Any advice on that?

& if I decided not to join such a program, what should I pay attention to?

Thanks in advance!