Sorry, I don't know any that are not pay for. Really one of the biggest things in the tests is actually understanding the format of the questions and the test itself. There will be things like multiple choice, place these things in order, match the definition with the word, fill in the blank, etc (at least that is how the Solaris 10 Certified System Administrator exams 1 and 2 were). You also need to be familiar with how to skip a problem and come back to it later since it is a timed exam.
I do have to say that the system admin tests were pretty intense, forcing you to know all the ways you can do something (for instance there are multiple ways to find all the patches loaded on a system, in real life, you really just need to know one, but on the test, you will need to know them all). And they will do things like make slight typo's in possible answers, maybe adding a space (which is hard as hell to even see with the fonts they use), or a uppercase "i" instead of a lower case "L" or vice versa (again, hard as hell to detect especially if you are trying to go through quickly).
For the system admin tests, Sun/Oracle has specifically stated that they remove the questions which the majority of the people get correct, and specifically build the exam such that 90%+ people will fail it. They don't care how it is that people get the question wrong, so long as most people do get it wrong (including by cheap methods like using bad fonts to mask typo's, or ambiguous questions which could have multiple correct answers, but one answer is "better" than the others according to Sun/Oracle). This is why they have a comments section for each question, where you can write down some of your logic and reasoning on selecting your answer. If you use the comments section, you will not get your grade back if the difference in passing/failing is determined by the number of questions you commented on until it is reviewed by their graders (otherwise you would get a grade immediately).