Jewelry Wholesale

Yesterday, I saw the price of jewelry at the Yayinjin Store in Xiangcheng, Suzhou. The price of gold was 345, the processing fee was about 12 yuan/gram, and the price of platinum PT990 was

Platinum PT950 price is 510 yuan, and the processing fee ranges from 80 ~ 150 yuan. Is this price expensive? I don’t know what the quality and after -sale? There are also sellers who say that platinum jewelery only has invoices and no authentication, but only diamonds. Is this like this?