There are lots of discussions about living cost in Shanghai, such as this one from Wang Jianshuo. I am not going to do a comprehensive study here, but I want to share my findings after spending one week in Shanghai.
I rent a one bedroom apartment near Zhongshan park, it cost me CNY 2,300. Because I stay for short term, they charge me a little higher. I think for a one year lease it will be 2,000 Yuan a month. A comparable apartment in St. Louis will cost about $500. So 2000 Yuan vs. 500 dollars. We can say one dollar is really worth 4 Yuan, not the offical rate of 7.75?