I reside in the UK and I will be in the US in November for a holiday. I want to ask whether its worth buying the iPhone 6s Plus whilst I'm there. The price is around £150 cheaper compared to UK with the exchange rate. I realise it'll come with a US plug but that doesn't bother me as i have plenty of ways to charge it. Is there anything else i need to consider? If i buy in San Fran is there any extra sales tax? If there is sales tax can i claim it back at the airport - how does it work? Thanks.