You are responsible for the taxes/customs/VAT etc if it exists. These are based on the value of the goods or the sum of the product price. The valuation method varies from country to country. The duty may also differ depending on the exporting country.

For EU :

The tax/VAT fee is already included in the product price. Therefore, EU preorder users won’t need to pay additional fees when receiving the package.

For US :

As we know, the Office of the U.S. Trade Representative recently published a list of 3,805 products (Chinese goods) that could be hit with the additional tariffs. The 3D printer is on this list. That means goods are worth more than $800 will not be exempt from additional taxes. We all hope that the tariffs will go away by the time we ship out the rewards to you. However, if the additional tariffs were in place at the time you receive the goods/rewards, you would be responsible to pay for this.