The CNA exam cost varies from state to state. If you were to challenge the nursing assistant competency exam in Texas you might pay a different fee than if you were to challenge the same exam in California. To find out the exact cost for both the written and the skills portions of the test in your state you need to contact the organization in charge of administering the exam. Pearson Vue is one of the companies responsible for testing nursing assistants in many states. Most states charge similar fees, usually not exceeding $100 for both portions of the examination.