You can call the local10010 for free at your home or roaming place;
If you add the area code in your country of origin, you can call 100 10 for free.
Add the area code when roaming, and you can call10010 in different places (including home) for free;
Answer China Unicom10010 for free in China (excluding Hong Kong, Macao and Taiwan);
In other cases (such as international roaming), the call will be charged according to the normal call charges.