It all depends on where you are and what you buy, I think. As an EU-citizen buying in the UK I have two thresholds to take into account:
- VAT over € 22 (as of the 1st of July 2021 this threshold is discontinued)
- duties over € 150
For example: I recently bought a few parts from Rimmer Bros, totalling some 85 euros. They charged me the amount ex VAT for the parts and warned me for the extra costs for clearing, duties, excise, what have you DPD would take care of. On entry of the parts in the Netherlands I got an email from DPD asking me to pay Dutch VAT on my purchases, but nothing more, because the total amount ex VAT for the purchase was > € 22 but < € 150.
I'm not sure how it works the other way around… Here's the explanation on the website of the Dutch government:
https://www.government.nl/topics/brexit/question-and-answer/purchase-items-from-the-uk-online-after-brexit. Dutch customs explains that duties on car parts are usually 3-4,5% of the total amount payed for parts, shipping and insurance. You are charged VAT over that amount. So, if I buy € 200 worth of parts at Rimmer's, another € 20 for getting it shipped to the Netherlands, I get charged say 4% on € 220 so € 8,80 for duties and another 21% VAT € 48,05 over € 228,80 totalling € 276,85 for my purchase at Rimmer's. So, the additional costs I pay for buying that particular part in the UK amount to the duties and the VAT over the duties (and maybe the extra 1% VAT I'm charged in the Netherlands, 21% VAT, as opposed to the 20% VAT in the UK).
Richard