To estimate the price of the 2018 Audi A6 35 TFSI I4 1.8L Turbocharged, I first considered the selling prices of similar cars. The closest match is the 2016 Audi A6 35 TFSI I4 1.8L Turbocharged with average condition, which sold for 45000 SAR on 2023-11-07. This car has a higher mileage of 255000 km compared to the target car's 206500 km. Another relevant data point is the 2016 Audi A6 35 FSI Quattro V6 3.0L Turbocharged, which sold for 55000 SAR on 2024-07-24, but it has a different engine and is a Quattro variant. Considering the 2016 model's depreciation and the 2018 model's newer year, I adjusted the price upwards from the 45000 SAR baseline. The 2020 Audi A6 45 TFSI Quattro sold for 125000 SAR, but it is a newer model with a different engine and better condition, so it is less comparable. Based on these factors, I estimated the market price for the 2018 model.