Marcia and André are very friendly and flexible hosts, we really enjoyed staying in their appartment. I can highly recommend the place for 3 people. Everything is brand new, clean and the location is great if you don't mind a short walk to the center! Porto is quite small in general and you can walk pretty much everywhere on foot, no need for public transport (and if you get lazy you can always catch an extremely cheap uber ;).
There is a small supermarket around the corner, nice breakfast cafe's nearby.