Selina's hostel is an Oasis in the middle of Aveiro with a cool vibe, cheerful and helpful staff and most importantly very clean and all the beds and bathrooms are big and well equipped. If you don't mind the noise outside of some of the guests at the common patio (it's even better if you are a night owl and prefer to have a chat and a drink before hit the pillow) then this is your place nearby the Univ, 30min from the airport, 10 min from São Bento station and well communicated with the rest of the city center. Just remember to bring your own lockers for your personal cupboard when sharing rooms and the rest will be chillax and enjoying the amazing Oporto! :-)