Please note the rules for taxes and VAT with international sales are quite complicated, and we only describe the relevant situation for antikvariat.net.
When ordering within EU, thus you as EU-citizen ordering from one of the Danish, Swedish or Finnish booksellers, you don't have to pay extra tax or VAT. The VAT is (if applicable at all) paid for in the country of origin. VAT-registered companies can in a few cases have drawn VAT, but only if the VAT-number is stated with the order.
When ordering outside EU, thus you from outside EU, or you as EU-citizen ordering from one of the Norwegian booksellers, you probably won't have to pay tax but your local tax office may charge VAT over the total value (goods + shipping). You may also be charged an amount by the shipping company for taking care of the import papers.
From the Scandinavian countries, only Finland has Euro as currency. When ordering across borders you must therefore be aware that you may be charged for bank charges as well (typically EUR 6-15), of course only after your accept. Many of the participants do however offer credit card payment or payment to accounts in other countries. Please require details when ordering.
Outside EU - return of additional VAT when returning an item
Please always contact your local tax office if you already paid and want to return an item to the bookseller. Note that returns must be made within 14 days of receipt of the item(s).