From the USA, want to buy a car in Spain

 My wife and I are both retired and want to spend 4 months at our house in Spain.  We have always rented a car in the past for 2 weeks to one month but the cost for 4 months is prohibitive.  We come every year and I think buying a used car and paying for for Spanish insurance may be less expensive in the long run.  I do not come from an EU member country so the rules that apply to me are different.  For instance, my American car insurance is not valid in Europe and I have to buy an international drivers license to drive legally in Spain.  Can anyone give me any advice about this or suggest where I can get answers to these questions?  Thank you in advance.

 US citizens are only allowed a stay of 90 days in any 6 month period so if you are coming for 4 months at a time, you would need special permission to extend that stay over 90 days.  Basically, the rules are the same as for an EU citizen visiting the States, 2 lots of 3 months per year.

Car insurance, depending on circumstances, is about €300 to €350 a year fully comprehensive (obviously depends on your driving record).  When buy a car, we were asked for an up to date "padron" which is the equivalent of the UK electoral roll.  I do not know what the procedure would be for a US citizen.

This site, whilst old, has information for US citizens which may answer some of your questions

US in Spain

 I think the 'padron' requirement may differ from place to place.

We have bought two new cars from dealers, one in Malaga province and one in Cadiz province, and have not been required to show a padron certificate.  Only the documents for our property and passport and NIE.