I can only repeat the words of Chen:
Very good value for the money! Garen is a very helpful and communicative host. The apartment (at level 0.5 of the house) was clean, appears totally safe, very comfortable and is located in a street, which is not the prettiest, but quiet (not so easy in Istanbul!). The appartment is very well situated, just a few minutes to Istiklal Street and not far from Galata Tower either. Have fun!