Jewelry Wholesale

Where can I pay by instalments when I buy Diamond couple rings? I'd like to buy one for 30 cents

I'm a jewelry salesman. Because I've just come into contact with this industry, I don't have much experience, so please do me a favor and try to be simple and easy to understand. there are also things about jade (how to introduce it to customers, how to communicate with customers, etc.)

Where is the larger wholesale market in Urumqi? Which bus? What kind of stall is more profitable? Thank you all first.