There are many opportunities for foreigners to accomodate. There are various ways to rent houses in Turkey. You can go to a realestate agency saying that you want to rent a house at a spesifik area or district. then he/she will make a search at his database and try to find the most suited home for you to rent. In return, he/she will ask for a certain amount of commission for the service her/she provided.
In terms of prices, We might say that, the general rule works here too. How? That's, areas or districts where social and economic life is active, transportation possibilities are good and accessible to many other places, located at a place near to the center of the city are highy expensive. If you are a student, you can share your house with a friend to decrease the amount of cost for the rent.