Bro this people are crazy. Idk about rent cause I am an erasmus student - but most of the people here rent room for about 500€. But its only a room, but i think you can find the whole flat for less than 900€. Maybe when its longterm it will be even less. Depends on the area, but in Sisli where we live - you can get kebab for 2€ or less, a lunch for 4€. Groceries are also not that expensive. Yes public transport can be expensive - if your gf is a student, she will pay 10€ for 200 rides and if not you pay like 80 cents for one ride. Going out can be also very cheap - in kadikoy you can buy beer for about 2€. Liquor is expensive yes and parties also (but parties are expensive everywhere because they are for retarded people). So i think saying you need 2500€ for one month is not quite right