First, it depends where you live, assuming its the UK, then they seem very much relaxed when opening packets from the USA etc. There is no tax to be paid on anything inside the EU, anything outside can be charged tax, but only if they open the package. I live in Germany, and the bar stewards open EVERYTHING from outside the EU, so i have no choice but to pay 7% on the value over 22 euros, under that is free, so i tend to either not buy outside the EU or ask the seller to drop the price on the customs label. I've also bought from an AU auctionhouse, and they had a very clever was of disguising what was inside. It was like a small book, to thick pieces of cardboard, when i opened it, it was like an advertisement for stamps etc, but taped under that was my 500$ worth of coins, very impressed