I live in Haikou, but have no idea where I can buy reasonable silk. I really like what I found in Singapore and Vietnam. Is it the same quality/price?

It may be hard to buy high quality silk products in that city.
So if possible, it is suggested to Shanghai and Hangzhou for buying some high quality products.
The silk products in Shanghai and Suzhou are much better than the ones you see in Singpore and Vietnam, I think.