If you reside outside of the European Union, you will most likely be able to claim back the VAT (value added tax 17.5%) you have paid. Make sure you keep all your receipts. Some shops, selling more expensive goods, operate a scheme for overseas visitors outside the European Union, to sell to you without VAT at the time of buying.
While in Edinburgh I withdrawed money from an ATM. To my surprise I did not recognise the money and realised Scotland have their own banknotes. There are actually three Scottish banks that issue their own banknotes today. The pictures on the notes are of Scottish Castles, famous Scottish people like Adam Smith and Robert de Bruce, and more.
Not sure I could change these money back to Swedish crowns too easily in Sweden I spent them before any with Queen Elisabeth II on it.
Scotland is proud to have its own currency. Three Scottish Banks have the right to print Scottish Pound notes. Only one of them prints a One Pound, note which is the only One Pound note in the UK.
The English notes are valid in Scotland and vice versa. Nevertheless, it is recommended to have Scottish notes when being in Scotland and get rid of them when leaving Scotland to England.
During a train trip from Edinburgh to York I saw an English waiter refusing a Scottish note of a woman who wanted to buy some refreshments ...
They have their own currency here but will take British Pounds as well. You will most likely get Scottish currency as change. It was no problem though because the rest of Great Britain accepts Scottish currency.
If you get a banknote stating 'The Royal Bank of Scotland', do not get scared. Scotland is a very independent land. They have their own national bank, which has the right to issue English pounds. At first I thought that the pounds issued by the Roal Bank of Scotland are acceptable anywhere in England (not outside the UK), but Hevbell, another VT memeber, informed me that it was not so: J1 Scottish banknotes are not acceptable in England, only J1 coins, as for the larger notes, they are acceptable but not everywhere. Another good tip from Hevbell is that there are 3 Scottish banks who produce their own bank notes.
Tipping in the United Kingdom is very much at your own discretion. If the service is good, then it is considered good practice to tip. The amount is up to you, but around 10% tends to be standard.