They did warn us 
We are very persistent. To be able to buy a subscription for a mobile phone, or a car, or a house, or to be able to open a bank account, as a foreigner you need a NIE number. NIE means: Numéro de Identidad Extranjero.
After numerous attempts (see They did warn us 1 through 9), we still do not have a NIE number. The last attempt was at the Policia Nacional in Motril. Through the Internet, we had chosen a date for an appointment. But we went there for nothing because I had misinterpreted the date.
Again I tried to make an appointment through the Internet. The Internet said: “You have a cita previa (an appointment) on Monday 12 February 2018, at 11:40 hours at the police station in Málaga.” We were on time and the receptionist gave us our allotment: number 56. As you can see in the picture it was almost our turn. And yes, at 11:45 our number was called.
The very kind and patient lady who helped us said: “Unfortunately, you have to solicit for a NIE number at the police station in the place that has the jurisdiction over the village where you stay. In your case that is Torre del Mar.”
My grasp of the Spanish language fell short to be able to express my bureaucratic despair. Why administer a multimillion-euro, totally computerized system, which functions outstanding, but not being able to issue a simple number from whatever police station that has a computer? Just because you are not at the police station that has the jurisdiction over the village where you stay? The NIE number is a national number. Once you have it, you can buy a car everywhere in Spain.
Although I have to make a proviso here because we have no experience of buying a car in Spain as yet. It’s very well possible you can only buy a car in the city which has jurisdiction over the kind of car you want. It’s even possible they don’t want you to buy a car at all. In fact, we are very fortunate to be able to buy fruits and vegetables at the supermarket or buy a meal in a restaurant and pay with a tarjeta (a bank card).
For the time being, we give up to solicit for a NIE number. All the same, no complaints about any employee at the police station, they were all very polite, kind and helpful.