Just got back from a week and a half in Spain. I was a bit wary of Spain's doubtful attitude to wild camping, so what I did was mostly use safe sites:
1. Barcelona - City Stop. Costs 30 euros but it's safe and quiet with facilities, very close to metro.
2. Vera - as my companion (my niece who lives with me) is named Vera, we had to visit the place named Vera! Unfortunately the "Oasis Al Mar" place was closed on 30 April (despite the owner having confirmed to me previously that they would be open until 1 May...) so we found a place at the Cuevas de Almanzera MH stop which was also good, 9 euros.
3. Went to see Granada, didn't know where it would be ok to sleep there, so we drove towards Cordoba in the evening and figured to wild it for that night. Guess what - Spanish roads, even non-motorways, do NOT have stopping places. Surprisingly difficult, very challenging, to find somewhere appropriate to stop! Much more challenging than in France, Britain, Germany, or *any* other country. Eventually I found a solution: fill up at a quiet filling station with parking area and ask to use their parking for the night. That was fine - problem solved!
4+5. Used the excellent (amazing!) MH site at Rhincon de la Victoria, just east of Malaga. Excellent! 10 euros per night. Very neat site.
6. On the way back north - as before, stayed at a very quiet filling station car park with their permission.
7. First flat area I could find just across the border into France at the Med coast (between Cerbere and Portbou). We did that on the last night before crossing into Spain as well, same place.
Was a pretty crazy trip for a week and a half but it was fun! I may post a more detailed overview with some pictures too.