There's a new Petrol Station just opened in the Estepona area (Western Costa del Sol) which is selling fuel significantly cheaper than the big chains such as Repsol, Galp and Cepsa.  The new petrol station is run by a company called Ballen Oil, part of Grupo Progeral.  I did some googling and can't find much information about them, so I don't know if this is a one off or if there are others in Spain. 

When they first started work on it, I have to say that I thought it was pointless having another petrol station as there are so many along the A7.  Well, I was wrong.

I went today and I paid 1.299 per litre for Diesel.  The next petrol station along (a Repsol) was selling diesel at 1.383 per litre.  That's a massive 8.4 cents difference.    In Marbella, Repsols were even charging over 1.39 per litre.

At Ballen Oil, Unleaded 95 petrol was 1.379, compared to 1.439 at Repsol.  That's a saving of 6 cents per litre.

For those that know the area, it is located in between Aldi and Lidl just off the A7, between Manilva and Estepona.