text:  A noisy market in China where shoppers interact with traders, a tradition that's been copied by supermarkets. So it's rare to see self-checkouts, largely because labour costs are cheaper. As Lil Jia Zhong, a writer and Chinese social commentator, explains. The migrant workers, they are originally from the countryside. Many of them have moved to the city to work. They are willing to accept a low salary and working for long hours.