I would be very clear on the paperwork about what materials are required and give them an option to bring their own, purchase their own or buy a kit when they arrive. Be very clear that time will not be taken from the class time to help with their materials, preparation or anything else you have told them to do. I know this sounds sort of harsh, but the students who followed your instructions will be grateful. Too often folks will take advantage of a 'newbie' because they know you really, really want the customers. Just keep in mind that the happy, prepared students will be the ones getting you more students! Tip - I would carry a small box of notions (scissors, pins, seam rippers, etc.) and let them BUY them if they forget theirs. Also carry an envelope with change and a form of credit card acceptance. I have 'square' and can use it with my tablet or with my phone. If you are planning on doing this as a business you need to be prepared. Your professionalism will be noted and people will treat you as a professional. Good luck, teaching someone how to make something is an unbelievably rewarding thing!