I saw a post on Facebook recently written by Sparks Electrical Services about electricity prices here in Spain which was really informative, it explained about how the marketeers here in Spain work and how they make their money and more importantly how to save money.
I sent a copy of my invoice to to Sparks and they changed me over to the regulated market with Iberdrola direct (Not Iberdrola Clientes) when I got my first invoice on the new tariff I couldn´t believe the difference, compared to the same period the year before I saved €40..