In bad luck case, one may have to pay an odd duty, however it have never happened to me while buying on ebay from China.
I think, there is a duty treshold and below certain value they don't care and probably there is a general exemption (one need to check).
It is a sad truth that we cannot afford duty war or (God forbid!) wider trade war with China. If that came true, our women would need to walk without panties because we are no longer producing these. Everything and anything would come to a standstill.
Our illusion of wealth is on Chinese license.
Disclosure of conflict of interest: My wife is Chinese. Best "purchase" of my life.
Martin