I plan to go to Spain for 10 days and drive around. I read on http://www.speedingeurope.com/spain/ (mirror) that speed tickets are half cheaper if one has a Número de Identidad de Extranjero (mirror):
If you have a spanish identity card (for foreigners this is NIE – Número de Identidad de Extranjero) you are wise to pay all fines within 20 days, you will then be given a discount of 50% – except for very serious offences. This means that the real fines are half of those shown below. If you do not have a spanish identity , all fines are to be paid on-the-spot. If you do not pay, the police may take your vehicle as security.
How can I get an NIE number for a 10-day trip in Spain, how does it take to get the number, and how much does it cost?
(I don't have any residence in Spain: I live in France and the USA, and I have the French citizenship)