If you are a jewelry designer, retail jewelry store, or any business that buys product from another company and resells it, you need a resale tax certificate.  Why?  Holding one allows you to purchase goods without paying a local sales tax. The customer you resell the product to will cover the sales tax for you.  Not only will it save you money, but it can help grow your business since you can purchase more products and pass the savings on to your customers.