Can I use 529 funds to pay for a CLEP test? How about CLEP test preparation materials? Title pretty much says it all.
No. Only for post high school education and associated expenses. The test is prior to entry. Unfortunately, this is a bit of a tough thing to document. "Not all expenses covered by 529 plans" is an article that touches on what's a permitted expense and what's excluded, but of course, an excluded list can't ever be exhaustive. One example from the article is that transportation to and from the school is not an eligible expense.
Since CLEP (College-Level Examination Program) is a series of exams to get credits waived, it's not educational or related to college attendance, per se, it would seem to me it's not covered. Of course, if one can find a legitimate source that definitively states otherwise, I'll reconsider my position.