Just came back from a trip to Spain!
and I stayed 4 nights at the Hotel Trafalgar
and I was very pleased. It cost me $222 for 4 nights (breakfast not included) for a single room that is quite small, but clean and comfortable. The room had a large balcony with a great view looking down Eloy Gonzalo and a view of the church at Iglesia.
I would really recommend the hotel for a single person travelling to Madrid. It is a very safe area, near Quevedo metro stop and a few steps away from The Plaza Olavide.