As an FYI, in the UK, sales tax (or VAT - Value Added Tax - as it's known) is 20%. However every price you ever see already has it included, including Amazon.co.uk. I guess it sucks that VAT is so high but it's nice that with prices, what you see is what you get. So if something costs 5 pounds and you pay with a 10 pound note, you get a 5 pound note back. Unlike the US where you'd get 4 dollar bills and a pocket full of coins which I always find a bit annoying. The fact that Lego is a lot cheaper in the US is very un-annoying though
(being English but living in the US).