If you're asked to pay when your order is delivered, this is because import taxes or duties have been applied to your order. This is not a shipping cost charge; all shipping costs are paid directly to HobbyLink Japan before your order ships. Import taxes and other fees, however, are charged by your local government.
For more information about import duties and fees, please see this article.
Please consider contacting your local post office for information about your country's fees. The more you know, the better you will be able to manage your shipments in a way that works for you.