To estimate the price of the 2015 Nissan Sentra I4 1.8L S (Base) in below average condition, I first considered the selling prices of similar cars. A 2015 Sentra I4 1.8L S (Base) with 166,000 km in good condition sold for 25,000 SAR on 7 Aug 2024. Given the target car's higher mileage and below average condition, its value would be significantly lower. A 2014 Sentra I4 1.8L SV (Top) with 325,000 km in average condition sold for 14,000 SAR on 9 Sep 2024, indicating a lower price for high mileage and lower condition. Listed prices for similar 2015 models with lower mileage range from 22,000 to 29,000 SAR, but these are in better condition. Considering the depreciation due to high mileage and below average condition, the estimated price is adjusted downward from these figures.