My phone with a US number no longer works--surpassed its tech lifespan. So, time to get a new US number. But how while living long-term in China? And without opportunity to visit USA.

I had thought about buying a U.S. sim card online, inserting it into phone I purchase here in China. But I don't know the tech ins and outs and gotchas on that.

Advice please.

Get a local US phone number from Skype:
www.skype.com/en/skype-number/

Depending on what you need the number for - you can also get free temporary and permanent mobile messaging numbers.

Your phone number is fixed to your SIM card. Normally you can transfer your SIM card to any other phone and keep your number. But I might be mistaken in this case; that is if your phone is bought as a package from a provider with all kind of restrictions.