Will admit, I have no idea what the costs are for the exams or certifications once the course is completed as I have not reached that stage as of yet. And I am certain that it all hinges on your area of interest. Go check it out and see what it would cost you, but don't forget to return and post about your findings. Of course, if you are already employed as say, an administrative assistant, or into IT, then at least you could impress your boss with the knowledge if you don't go for the exam or certificate right now.
It's worth looking into. WILL SAVE GAS!!!!! And you can complete it on your precious time.
Just FYI

http://www.microsoft.com/learning/default.mspx