To estimate the price of the 2015 Hyundai Elantra I4 1.6L Smart (Base) with 155000 km mileage, I first looked at the selling prices of similar cars. The closest matches are the 2016 Hyundai Elantra I4 1.6L Smart (Base) with average condition and similar mileage, which sold for SAR 30000, SAR 27000, and SAR 28000. Considering the 2015 model is a year older, I adjusted the price downwards. The 2015 model with 216000 km sold for SAR 34000, but it was a GL (Mid) variant, which is typically priced higher. The listed prices for similar 2015 models were SAR 32000 and SAR 31500, but these are generally higher than actual selling prices. Based on these data points, I estimated the market price by averaging the selling prices of the closest matches and adjusting for the model year and mileage.