Hostal Arkanta 

We went to Arganda Del Rey for a wedding and didn't want to pay a lot so found this hostel for £28 a night room only. The earliest booking in time is 15:00 but the girl on the desk allowed us to book in at 13:00 ( we just wanted to leave our luggage until the booking in time). They say that the staff are multilingual but she could only speak Spanish, Google translate and sign language come in handy. The trip from the airport took an hour on the metro (2 changes) then a 10 minute walk. There is Bar Iris on the way it serves great coffee well worth a stop. The rooms are clean have a tv with digital channels a fan that is quiet considering the size of it. Water pressure of the shower was strong and temperature was easy to control unlike some other high priced hotels. If you want breakfast there are plenty of cafés and bars around. Whn I go back to Madrid I will certainly think about going back here as Arganda is a friendly place and the metro gets you to the centre of Madrid in half an hour. You should buy a 5 day tourist ticket which lets you go to all the stations on the metro, other tickets limit you to certain zones