The local currency is not convertible outside China, so if you have any leftover you will need to change it back before you leave, or at your departure point. Make sure that you keep one or two of your exchange receipts, which you'll need to change it back again. You can exchange renminbi for Hong Kong dollars in Hong Kong.
Cash withdrawals from Visa and MasterCard credit/debit card are possible at the main branches of the Bank of China in each city. A small fee is charged by the bank and charges are also applied by the bank/credit card provider.
Western Union is available in China although fees apply to transactions. Check the western union website for locations.
Taxes and Refunds
More information can be found here.
Weather in Shanghai
Wireless Internet Access
The foreigner group tour guides and drivers depend on this tip income, along with shopping stop commissions, to form the bulk of their income. The shopping commissions come from the merchants paid to the guides and drivers in return for stopping at their establishments. Prices are raised at these group tour shopping stops in order to pay the commissions up to 50%.
While tour drivers many times expect tips from foreigners, taxi drivers in China will not accept them. In most places, tipping taxi drivers is against the law, so ingrained is the Chinese culture to not tip. Many Chinese consider tipping a remnant of the Chinese warlord and feudal system during the Empire period ending over a century ago.
Since tipping is not a part of the culture, most establishments actually have a strict no-tipping policy. This includes almost all restaurants, massage studios, etc. In fact, offering a gratuity may be considered impolite in certain quarters as it can be taken to imply that one's work is undervalued by the employer. The only place where a tip might be expected is at a high-end hotel catering to western tourists. And the only reason tipping may be expected there is because western tourists have conditioned the behavior of bellhops and concierges. Still, declining to tip will not offend the service worker. And if you have someone go way above and beyond their normal duties, then a tip might be appropriate.