Got invited to offer decorating classes in public libraries. How do we go about the pricing? Charge per attendees or per hour. note: we bring the decorating supplies. 

Thank you in advance. 

Definitely charge per person   You must supply everything so be sure to carefully work out that price   I foresee a problem w/o the means for cleanup   Icing will get everywhere — even with caution 

yes what lynne said ^^^ fwiw royal icing is so much easier to clean up than buttercream