Just remember where you are making the order from and where the order is being processed. If you are in the EU (European Union) you will pay Vat at the local rate (local where the purchase was made). If you a business and have a vat number you can have the inter EU purchase made excluding the local Vat rate. If you are outside the EU the you will have the purchase Vat exampt (as far as I know).
Unfortunatly not all business on the web in the EU offer the business Vat exempt. I have a photo business in Ireland (part of the EU and the Euro) and I have only found very few on line businesses that will deal vat exampt even when I produce my Vat number. Some businesses don't even know about Vat exemption and how it works. I understand most on line businesses are retail not b2b but there is business there for b2b if they are interested. (b2b means business to business just incase ....................)