I had a pleasant stay at Margaridas house. A small but very cosy room that provides everything you need. Shared spaces like kitchen and bathroom were always clean. The household also includes a cat and a dog, both were super calm and nice when I was around. Bus station is just around the corner and Belém in walking distance. You should be aware that it will take you some time to get to the busy part of Lisbon.
All in all I can fully recommend staying here!