I'm not sure that he did. However, let's say he did have the exemption, am I still liable for the tax if I didn't agree to purchase the parts from him? In other words, he never made it clear to me that I would be purchasing the parts from him. All I agreed on was the final cost of the project and to reimburse him for the parts that he needed for it. Once again, the whole reason why I let him purchase the parts instead of ordering them myself is that he assured me that he could get a better deal on them. I never agreed to "buy" the parts from him.