I had a really nice experience at Karla's place. The flat is located in a strategic point where you can easily access any (touristic) part of the city even by walking, and the price is reasonable (cheap, really). Karla and her family are very kind and willing to help you with everything you may need. You can have access to a well equipped kitchen, and everything in the place is clean. As there were several people in the flat when I stood, it seemed a little like a hostel, but for me it was not a disadvantage but the opposite: we had nice talks and we made friends. But if you are looking for a more private place, probably this may not be the one.