The actual cost is equal to the parcel fee plus 3 yuan registration fee plus 0.5 yuan certificate fee plus insurance (voluntary). According to the query of postal express in official website, the charging standard of ordinary postal parcels in China is that the actual cost is equal to the parcel fee plus 3 yuan registration fee plus 0.5 yuan document fee plus insurance (voluntary). When ordering postal parcels, the system shows that the expenses are the actual expenses. The first weight of the package shall be calculated as 500 g, and the continued weight shall be calculated as 500g, and the part less than 500g shall be calculated as 500g.