Hello, I am renting out my room daily and weekly in September, mostly you will be alone, i have everything at home you need, self cooking is also possible as the grocceries and the shops are just a steps away. There is a good chance to experience Turkish culture staying in a local place, Sisli is one of the main centre of istanbul and its one stop away to Taksim. Price: 30 euros per day (up to 4 days) 20 euros per day (5 days and more)
Please feel free to contact for details.
*i have very good experience with short term visitors and expats so reference upon on request :)