NOT KNOWN FACTS ABOUT RELIABLE ISTANBUL AIRPORT TAXI

We have been 6 arriving to the new airport in august gonna beykoz island, what transport could you advise can be much better and kind of the amount can we count on to pay for ?The worst point is always that at no issue do they convey to us that we must pay for it, only once the race ends.Certainly one of the most important procedures you need to kn