European businesses can buy ex VAT.
You will find the VAT field in the checkout, just before the payment step. Enter your number there — it is verified automatically, and once approved the VAT is removed from the total before you pay.
If the number is not approved, do not continue. Once you have paid including VAT we cannot reverse it. Mail us first and we will sort it out.
Your VAT number needs to be valid in the EU VIES register.
Dutch customers always pay Dutch VAT. You reclaim it yourself in your VAT return.