Pinar's Airbnb at 83 Kurdela sok, matches the description you get. It is bright, clean and basic. Comfortable but not luxurious. But fair value for the price. Pinar provides good directions online and there is someone to meet you when you arrive even if she can't be there.
While the Dolapdere area is a little rundown, there is a brilliant street market every Sunday. You are conveniently placed for the main roads into the centre (after a steep uphill walk) into Taksim and into the Old City.
Although you have your own bedroom, the flat and facilities are shared so you are taking a bit of chance with your flatmate but mine was fine.