The customs is a government agency entrusted with enforcement of laws and regulations to collect and protect import-revenues, and to regulate and document the flow of goods in and out of the country. Not to be confused with custom.
Its first responsibility is not only the collection but also the safeguarding of customs duties.
This management of customs duties is essential for controlling the flow of goods in and out of a country. Therefore, the customs process begins in the country of origin and ends in the country of destination.
As there are different regulations for customs and taxes in different nations and economic regions, e-tailers face the problem that the prices they show in their online-shops are not the final prices because of this different customs taxes. In some cases the e-tailer maybe doesn't know the exact regulations of the country of destination. This regulations could raise the final price. Customs regulations could also be prohibit the shipping of certain goods to different countries.
— Johannes Matheis 2011/12/22 22:15