When importing goods, travellers must basically pay the import charges that are due on the goods purchased abroad. Depending on the goods, these comprise customs duties and other import charges such as VAT on imports, excise duties on tobacco, beer or alcohol.
The purchase price is the basis for calculating the amount of the import charges. You should therefore keep the sales receipts or invoices for the goods bought abroad. Whenever you cannot document the purchase price, the prices of comparable imports of purchased goods will be taken as a basis. The value will be estimated, whenever the customs officer does not know these prices, or in case the goods were not purchased but given to you as a gift, for example.
Whenever the price includes a VAT amount, this amount will not be included in the basis of calculation, if you can prove that the goods were or are VAT-exempt from value-added tax in the country where the purchase was made and that you, as the buyer, are the beneficiary of this exemption. The amount of the import charges therefore depends primarily upon value and rate of duty.
The excise duty on tobacco is calculated based on the retail sales price.