China Unicom has a 3 gigbyte SIM for about $55. It worked extremely well in our Samsung Android Tablet everywhere we went - city and rural. Never a dead spot. (Piranha uses the same carrier - never saw loss of signal. At times set up the tablet to act as a hot spot for wife's old ipad.
I knew this rather new SIM was available before leaving. I figured it would be easy to pick up near our hotel in Bejing (first stop). Didn't look too hard because didn't have an immediate need.
Won't go into details - but regular shops that sell SIMS don't carry this. Had to locate a company store. Few people are really fluent in English - but did locate store in Shanghi a few days later. Dropped the SIM in the tablet and it immediately started to work. I was afraid there would be complicated instructions in Mandarin to read in order to set it up.
MISTAKE I made - China blocks internet access to Facebook, Youtube, AND NY Times and CNN websites (among lots of other things.) I should have set up a VPN service before arriving. I had never done that before.
There is a dealer:
China 3G Mobile Broadband / China 3G SIM card, for rental, hire and sale That will deliver your data SIM to the first hotel you arrive at and pick it up from the last hotel AND provide you with a VPN to use with the card. I think the total cost for renting the SIM from them for a month (3 gigabyte pkg.) is about $75.
mike
Make use of T-M's UMA/wifi free calling from any place in the world with access to wifi. I use an LG G6, wife an S7)
A/o Oct 20, 2013 no need for intl prepaid as T-Mobile U.S. includes voice roaming at 20ยข/min (in and out)., unlimited text (in and out), and unlimited data in 140+ countries.
My Plan -[6 lines] U.S. T-Mobile unlimited minutes (incoming and outgoing), unlimited text, fast data on each line. that $145/mo. total! . (In U.S. no surcharge for calling a cell.) If a line exceeds 2G of data in a month, pay $10 more for that line. [That only happens a couple times/year.