It really depends on how big or how heavy your parcel is, how fast you want to send it through, or if you want an insurance or the tracking information along with the parcel.

In general, if you want to send a small parcel which is less than 2kg, post office offers a competitive price with their Surface Mail service. It costs £14.61 for sending a 2kg packet to China, but can takes up to 8 eight weeks. If you think 8 weeks is too long, you can try Airmail which takes about seven working days. If you want to have online tracking, you can try Airsure.

For parcels over 2kg, its better to check other parcel services such as Worldwide Parcel Services, Transglobal Express and etc. You can get instant quote by using their online services.