Cost of Living in Istanbul
The cost of living in Istanbul is lower than in many other european cities, but it is higher when compared to the rest of Turkey. There are much more social activities to spend money on in İstanbul compared to the other cities in Turkey.
Usually students in Istanbul spend around 20000-25000₺ per month, including accomodation, food and transportation expenses. However, the amount of money you will need depends on your lifestyle. If you plan to travel to different parts of Turkey, you will definitely need more money.
Check: https://www.numbeo.com/cost-of-living/in/Istanbul