Key GSM providers in Turkey are listed below:
Pre-paid cards
The prepaid SIM card with a world cell phone is a convenient, economical and
efficient way to stay in touch while in Istanbul. All incoming calls while you
travel in Turkey are free. You only pay the local rate for local calls since
the SIM card is prepaid, there is no hassle of a contract. You can get a pre-paid
SIM card at any mobile shop in Istanbul.