Clep Tests

Has anyone ever taken one? I am signed up for the "principles of Macroeconomics" clep test. It will be SO good if I can test out of it - less expensive, less time consuming, less trouble - but it will be SUCH a waste of 70 dollars and an afternoon if I don't pass it. If I do pass it I may try for another, but I'm going to wait and see how this one goes. I have no background in the subject area, I've just been reading a textbook. My test is on Thursday. Has anyone taken a clep test before? (The macroeconomics one or any other) What's it like? Is there anything to watch out for? I know it's multiple choice, but not much beyond that. I don't even know if it's on paper or on a computer or what.