Is there a free VPN for China?

Is Surfshark usable in China?

You should ask your provider in China for answers about where they are allowed to sell their products.

I do not know if you can order from them online, but most providers will have a local office or person in charge of orders. You might want to call them up and ask their legal department. Their contact information is below:
It looks like this should be possible - the US version uses PayPal as the payment option. I've tried this, and it went through without any issues. When I tried to get the tracking number they used by email, I received an email response back from someone in the UK within minutes. I think you may need to use another form of payment.