Advice on taking CLEP!

[SDdude]

Hey everyone, how are you guys?
I'm going to be 24 this July and have never attended a day of college in my life. I decided not to attend college after high school, which was back in 2004.
I plan on attending a community college for 2 years or so before transferring to a university.
I did so-so in high school, I honestly did not have the best of grades and have below average grades in certain subjects like math/science, etc.

I was thinking I can score some credits with CLEP and maybe skipping some intro classes and whatever else is possible.
I ran into a number of sites such as instantcert.com, domeactreview.com, cleptestreview.com, passyourclass.com and speedyprep.com

Do any of you in my similar position have any experiences with these sites and any other ways of learning, studying, prepping, etc. that has helped you pass these tests?
I'm not too big on school but figured it would be something to fall back on and looking forward to going back to school the next semester.
Thanks in advance guys!