I would just stock up on USA iTune gift cards when I lacked a US credit card. Its not hard really, the real problem are Chinese apps that you might need for your day to day life (e.g. the dedicated Didi dache app if you didn't want to go native and use WeChat). Even then, Apple seems to let you change your app store easily, you can even have apps from both the US and Chinese app stores on your phone (or at least, that was true a couple of years ago).