Shanghai

What is the cheapest way to fly from Singapore to Shanghai Pudong Airport?

what are the things to look out for? What are the rules like a list of do's and don't? what are the things to keep in mind? Can anybody please share their life experience in a hotel in shanghai or a personal story with me? As a foreigner, what are some of the things to be beware of. By the way, a hotel room with two beds, a single bathroom and a television, is that a 3-star or a 4 star hotel?

Thanks for the response. I guess Wang's 2.5 million is including domestic migrants working in the city. I know there is about 450,000 expats (foreigners only but including HK, Macau & Taiwanese) in 2006. I just trying to find out the number now. :) I'm doing research.