This was easily my best experience with AirBnb.
Not only is Eyüp’s place very economical, it's at a great location walking distance from the Galata Tower and Isteklal Cadessi with great cafe's and bars. I highly recommend trying the Turkish Bath in the apartment. It is AMAZING. it made our day after running around all of Istanbul in the rain.
Lastly, Eyup is a great host. He was readily available with directions when we got lost (sadly this happened multiple times). I highly recommend Eyup's apartment and will definitely make it my regular residence when I vist Istanbul again.