Shipping from Dr. Diff in USA?

Have ordered a few things from Dr Diff. 3rd member which he delivered to warehouse in sweetgrass and I went and picked up. Other items small and he sent by post. No duty I recall as US made, under free trade and classic car parts. I order lots of other parts for my other cars in US and almost always use post unless I need it faster or supplier won't send it by post. Won't use courier if brokerage fees unknown and UPS last resort.