If you wish to stay literally 5-7 minutes away from Taksim Square for an affordable deal, Okon's place is the right choice.
Okon was humble enough to tell me Taksim Square is 10-15 minutes walk but trust me the walk is way less than 10 minutes.
To reach Taksim you have to cross the main street nearby his place. If you continue your walk towards your right hand side you end up in Taksim Square and if you continue walking towards your left hand side after crossing the main street you end up at great bars/pubs/night club/fruit shops/etc etc.
Under his place there are 2-3 super markets which are open either 24/7 or until late. They accept both Cash/Card plus there's also a resturant for great local food.
Lets talk about his place. It's more like home away for home/super clean/modern /New. Great place for a couple with an infant/child or 2-3 Adults. Comes with a balcony in the living hall and city view from bedroom.
Okon's place is my new home in Istanbul, ain't goin anywhere else.