Originally Posted by
paul4040
I can't help with costs but the taxis in Istanbul are all metered.
Finally, I would recommend contacting the hotel directly to arrange a private transfer. The cost will then be fixed and you'll have the security of someone reputable waiting for you when you arrive at the airport. Istanbul is a surprisingly tourist-friendly city and while it has its fair share of con merchants, is certainly no hotbed of rip off activity.
The cheapest transfer offered by the hotel is TL385/TL690 (one way/return) for a Merc E Class or BMW 5 series. So, I am going to take a taxi.