I don't know if they still do it, but some years ago when I lived in the UK and later when I ordered something from amazon.co.uk while visiting, some items such as DVDs, which were marked as "sold by Amazon" were actually shipped by a channel islands (Jersey?) based company. The channel islands aren't in the EU or the UK's VAT system, so by splitting the order into shipments below the UK's import VAT threshold, they could avoid charging VAT. I don't know if that scheme still works, as non-EU businesses that do above a certain amount of EU based trade need to register for EU VAT. (including getting an "EU" prefixed VATIN)