If you decide to spend a few days in Istanbul, I totally recommend Byr's place. It is situated close to the Grand Bazaar(we walked and it only took us about 10 minutes or less), close to the sea and the Hagia Sophia or The Blue Mosque . (again about 10 minutes walk).
The place where we stayed was very clean and peaceful.
Byr and his uncle were very helpful when we needed any help or information. Thank you very much for everything!