Anyone who is looking for a place to explore Lisbon cheap and comfortably should consider Carlos's apartment. Here are some reasons why:
1. Location, location, location. The apt is only a few minutes' walk from the Avenida metro/subway station near the fashionable Avenida da Liberdade. This was a great selling point for someone who prefers to use public transportation to get around when traveling.
2. Quiet and safe. Although at first glance you may think the street is a little sketchy, it is not. Very quiet and safe. I felt no problems walking back after midnight.
3. Cheap. The apartment was much cheaper than hotel stays nearby, and you get to experience living in a Lisbon bairro like locals would!
4. Carlos himself. He was on hand for anything I needed and to give any help as to where to go or what to see. I appreciated his advice (especially checking the bars in Bairro Alto to experience a night out Lisbon style!). He was funny, considerate and a great host even though I mostly stayed to myself because I wanted to explore as much as Lisbon as possible in a short time.
The only issue I had (and it was a minor one) is the bathroom. The step up is a little steep, which can feel daunting when leaving the bathroom after taking a shower. And I was taken aback by the open shower head with the toilet and sink, but overall I enjoyed the place and would recommend and stay again in the future.