Jazztel looks like the best option to save money but unfortunatly my area wasn't serve by fiber optic. I have Movistar at the moment but it was so hard to have it install and the customers service is really annoying, especially in the shop where they only tell you to call the call center.
the other option are Orange and Yoigo.
All the operetor have really similar offer except jazztell wich is cheaper but they don't have a shop you can only apply by phone or internet.
This are all the operetor wich i find in my area but probably there are other offer around.