The reason why slow charge will be so cheap, the principle is like this: when the merchant receives the recharge payment, it will not immediately send your payment request to the mobile operator, but after the accumulation of many people's payment request to the mobile operator. In this case, the amount of network communication is only once, and the amount of a single submission will be relatively large, and you can enjoy the cost concessions provided by mobile operators. Just like group buying, \"slow charge\" is slow in the business to gather the number of people, cheap because more people can buy concessions, the fee is low.