I would make one, only one, and keep careful track of the cost of materials and the amount of time it takes you. Figure out how much you expect to make for your time, and that plus the cost of materials gives you the minimum you would accept from the shop owner. Take the item and the price to her and see if she is interested in buying from you at that price. Don't forget that if you make a profit selling items you will probably have to pay 15% of it for social security and medicare taxes, and you may have additional business expenses, such as a business license. Good luck.