Why are imported things so expensive and exported things so cheap?

This is related to the exporters I have been to. First, let's take Barbie dolls in America as an example. It is sold at an ultra-low price in the United States, but it is sold at an ultra-high price in China. Why? China is not much richer than Americans, because their exporters are determined to keep prices down when doing foreign trade. In China, many exporters always say that it is difficult to export now, which is true. China's foreign trade seems to have always believed that the more orders you take, the more you will earn, so that in the process of taking orders, you will often offer terms that you can't imagine sometimes. Even if you sell at a loss, you should keep your customers, thus keeping the export price down for a long time, but keeping the price of domestic products unchanged. Another is national policy. You know, what I said is that politics determines the economy, not politics and the economy of some countries such as the United States. Countries would rather do business at a loss. Can't they reduce the price of export goods? But foreigners don't think so, so the prices of imported goods are very expensive.