The cost of the fabric (not including any discounts), all the notions, including thread (just because you have it on hand does not mean you you have to give it away , you WILL have to restock). Your time purchasing, cutting, sewing and finishing the item...not below minimum wage per hour of said time. Plus, add in some amount for agrivation and driving time to purchase supplies...that is well earned money. Oh, and ask for a deposit for the fabric, why should you pay for it? They think the cost is too high? "We can buy them at Walmart for less". Explain to them that you will not be upset that they choose to not use your "expert and professional services to produce a high-quality garment, custom made to meet their expectations and your quality of standards". Suggest to them that you will be happy to take their measurements in order for them to purchase these quality garments for $10 to 15 at Walmart, but of course, those measurements will mean nothing to any associate working there. DO NOT GiVE YOURSELF AWAY!