PAY AS YOU GO MOBILES IN SPAIN

THE RULES FOR EVERY SPANISH PAY AS YOU GO PHONE

regardless of how much credit you have (one myth out of the window)
you must TOP UP EVERY 90 DAYS
AND if you DO NOT TOP UP for SIX MONTHS
YOU LOSE YOU MOBILE NUMBER

I have picked HITSMOBILE as the company that i use around the island ,one of the main reason is the coverage comes from vodafone.
their web site is in english
http://www.hitsmobile.es/en/web/guest/home
and you can ring then ,also in english on 0800 654 321

they also have a KEEP YOU LINE ALIVE service
where you can pay €10 and you phone will stay active for 12 months regardless of the top up rules

THE RATES are for those with AUTO TOP UP (that is when you are low it dips into your bank for some money are 3c /min to fix and other mobiles .
if you just top up as normal the rate is 5c /min ...
http://www.hitsmobile.es/en/web/guest/recarga