A part from very wide choice of good hotels in Lisbon these are other possibilities. I recommend you to think about renting a flat as the cost are sometimes really amazing and you have the whole flat for you! Including kitchen!
Booking.com
If you plan to stay in Lisbon for example for a mont - check on olx.pt where you can find a single room for 200 - 250 eur per month. As Lisbon is a popular Erasmus participants' destination, many owners speak and advertise in English.
(olx.pt / imoveis/ quartos para arrendar)
