To estimate the price of the 2018 Mercedes S450 V6 3.0L Twin Turbo Standard with 139000 km mileage and average condition, I first looked at the selling prices of similar cars. Two cars with the same specs and good condition sold for 226000 SAR and 215000 SAR in early 2024, but they had significantly lower mileage (58000 km). Considering the higher mileage and average condition of the target car, a downward adjustment is necessary. Next, I reviewed listed prices of similar cars with higher mileage and similar specs. The listed prices ranged from 210500 SAR to 265000 SAR, but these are generally higher than actual selling prices. The closest match in terms of mileage (150000 km) was listed for 210500 SAR. Given the average condition and higher mileage of the target car, I estimate its market price to be slightly lower than the lowest listed price.