What should I charge as a marketing consultant?

A company has recently asked me to consider isting them with making marketing brochures and fliers for their investment firm. I am by no means a professional but am doing this on the side. I usually produce quality material for non-profits but this is the first time I have been asked to be a consultant for profit. How much do consultants usually charge? As a novice, what would be reasonable? Looking for some input. Thanks!!