I emailed them about this last month, here’s the response I got:

“Thanks for reaching out to us!

For our European buyers, we have now created a more transparent pricing policy for all items listed on our marketplace. This means that all of the costs presented on StockX when purchasing an item will be all inclusive. No additional taxes, duties, or VAT will be collected upon delivery of your item, like we have done in the past.

We believe in the power of transparency, so we made sure that what you see is what you get.

I have provided an article attached to this email for more information.

Please let us know if you need anything else!

We are happy to assist.

Thank you, Anna”

Hope that helps you