money and methods of payment

Money

The currency in Spain is the Euro.

When changing money, you should always use official money exchange offices or banks, as possession and use of counterfeit money is considered a very serious crime in Spain and may lead to prosecution.
If you are travelling to or from a country outside the European Union you must declare any cash of over 10,000 euros or more (or the equivalent in other currencies) to HM Revenue & Customs. 

Credit cards and ID

When buying goods in Spain with credit/debit cards, all al customers, regardless of nationality, must show ID. You may be able to use a driving licence or a photocopy of your passport, but you may be required to show your passport.