If it is a Import car you have to pay more than 67% of Tax, but if it is a car which is assembled or build in Turkey (such as Fiat, Toyota, Hyundai, Renault) you'll have to pay about 43% of Tax, and I mean V.A.T. as Tax
The normal Tax for a 1.6 lt. Engine car with weight of 1.1t ranges from model year from 140€ to 220€ a year. (It can cost you much more if it is a Import car). Maybe the price of the Fiat Coupé 2.0 20V Turbo is so high because there were only 3 of them imported.
By the way do you mean Beyoglu (it is pronounced Bay-oh-lu) ?