Through Travelocity, I booked a double room w/ kitchen & bath for 42 euros per night at Apartamentos Turisticos Principe. They are on Calle Principe, off of Carrera de San Jeronimo. Very well located, near the Prado, Puerta del Sol, etc. Won't be staying there until July, so I can't tell you how good it is, but it seems nice enough from their pictures. Their website is www.atprincipe11.com but you have to go thru Travelocity to get that rate. Hope this helps