For International Shipping, customs has the right to impose an additional fee or VAT. The fee varies by country and we are unable to calculate this in advance.  Fanjoy is not responsible for the payment of this fee.
Using the UK as an example, they state they will charge VAT on any shipment with a value greater than £15, which equates to approximately $23.27 USD.
You can read more about import taxes and duties for the UK here:
https://www.gov.uk/goods-sent-from-abroad/tax-and-duty
Taxes will vary from country to country, as will tax enforcement.  We have found Canada and the UK to be among the countries with the strictest enforcement, unfortunately.  At any rate, this is an extremely common issue for international customers.  For folks that are especially upset or feel they were unlawfully taxed, we recommend they contact their customs office to file a dispute.  Customs offices will have forms available where their citizens can file their dispute, like this one for the UK:
https://www.gov.uk/government/publications/import-and-export-application-for-repaymentremission-c285
If you have questions, feel free to reach out to us directly at hello@fanjoy.co