ACCOMODATIONS IN INSTANBUL

I would ONLY stay in Sultanahmet area.
Unless you totally want to miss the Turkey culture... Not really but more than in the modern side... Hyatt and such.
Tourist .. Best Western is most cultural.
Party people. Orient Hostel.
Cheap Hostel and very nice and calm. Antique
Cheap room and very nice. Admirials.
There are lots of rooms for around 25 Dollars that I would feel is good for anyone.

Hostel Dorms are 10 Million per person.
Cheap rooms are about 15 Million.