Will instacert work well for me ?

[jm82792]

I'm 16,am a ged grad(550,Killing myself over the score)
and am going to take some cleps since I need credit to UH Hilo and these cleps go towards my degree.
Sociology,Microeconomics,History of United States 1 and 2.

Now for somebody who has graduated,doesn't know a whole lot about history,nothing of micro economics or sociology would REA books and then instacert be a way to pass ?
What is instacert ?
How does it work(flash cards and clep like Qs)?
Is it to check if I know what I'm doing after REA and other sources,and help me score higher?

Are the REA books good ?
I have micro economics and sociology coming in the mail.
Amazon says microeconomics is okay and sociology is good,however I'm not sure how factual the information is.

Any advice on prepping for the clep ?
How long does it take to build from knowing almost nothing of a subject to passing a clep?