Cellular phones are commonly used in China and offer generally good service. They play an essential role in daily life for most Chinese and expatriates.
If you already have a GSM 900/1800 cell phone, you can roam Chinese networks. However, calls are expensive (12-35 RMB/minute). A local SIM card for 3G data access can be inexpensively purchased to resolve this issue. This also gives you a Chinese phone number with a certain amount of money preloaded. Note that Chinese may avoid phone numbers with the bad-luck digit '4', and vendors will often unload these "unsellable" SIM-cards to foreigners at a discount. If you need to buy a phone, they can usually be purchased for around 100/200 RMB used/new. Chinese phones, unlike those sold in many Western countries, are never "locked" and will work with any SIM card you put in them.
It is also possible to rent a Chinese cell phone from companies like Pandaphone for about 7 RMB a day. When renting a phone, an access code is given for calling your country, which is cheaper than buying a SIM card from a local vendor and dialing directly.
The typical expat spends a few hundred RMB buying a phone for full service, and usually pay about 100 RMB a month for the service. Incoming transmissions (video/voice call, text) are free. Calls are around 1-3 RMB per min and text messages are about 0.10 each. There is usually a student plan available (66 RMB for 50 minutes, 240 texts).
China's two big operators are China Mobile and China Unicom. Most SIMs sold by the two work nationwide, with Unicom allowing Hong Kong/Macau/Taiwan usage as well. Watch out for SIM cards that are only useable in a single province. You may also need to manually activate national roaming, which may incur a small daily surcharge as long as it's active. Avoid the cheaper wireless phones called PHS that only work in one city.
International calls have to be enabled separately.
With China Mobile - Called 12593 service. Requires a 1000 RMB ($151 USD) deposit to enable this service. Generally cheaper than China Unicom at about 0.4/min to North America.
With China Unicom: Called 17911 service. China Unicom's works by default.
Once the service is enabled, punch in the code before the number you want to call and dial.
Data packages may include nationwide minutes, videocall minutes, 300MB data, and included multimedia/text content (ring tones, mobile news reports, wallpapers, music videos, etc). Packages start at about 96 RMB/month. for 240 ).
Pay-as-you-go plans are also available for those that not interested in signing up for a contract. These can be purchased just about anywhere, at any kind of media store. To recharge, visit the neighborhood office of your mobile service provider. You are able to give the staff your number and pay cash to recharge the account. If you prefer, many shops will sell you a charge card, which has a number and password that must be used to call the telephone company to recharge the money in your account. You will be calling a computer and the default language is Chinese, which can be changed to English if you understand the Chinese. Charge cards are sold in denominations of RMB30, 50 and 100.
Unicom allows you to re-charge with a local bank account if you understand Chinese. Accounts can be recharged by bank transfer online. This is cheaper and sometimes there will be special offers for recharging this way.
China Mobile offers an "Easy Own" prepaid card. This offers 100-200 RMB for 1 or 2 GB of data a month. It's possible to de-/activate this service with a short message to the number 10086. There is also a 5G cap (maximum charge per month) of RMB 500.