What is the cheapest way to ship 30 kg package to the Caribbean (Antigua and Grenada)

Hi, the cheapest way to ship the package to the Caribbean is transported by SAL parcel service and the limit of the package is 20kg, so you need to divided it into 2 parcels. The fare is about CNY 2300 in total. The cheapest way to ship to Guatemala is by surface and it also need to be packed two parcels. It costs about CNY800.