Getting from the airport to Istanbul center is the first thing that sets a budget trip apart form a luxury.
Sure, a taxi is only 8€, but you have to find one first. Make sure it’s a registered one and not a fake one dropping you somewhere. Get small notes beforehand, so you can give exact change or it will be “no change sorry”. Even though you make sure a meter is ticking, then you follow the route on your phone to make sure the driver doesn’t drive a huge detour.
We just took an Uber – a black transporter with leather seats, charger for your iPhone and toned windows. It was 11€.
On the way back to the airport, we had the hotel call a taxi and there was no problems. So maybe the rumours are only justified when arriving.