To estimate the price of the 2021 Chevrolet Spark I4 1.4L LT (Base) with 128000 km mileage in average condition, I first looked at the selling prices of similar cars. The 2019 model with 120500 km sold for 26000 SAR in November 2023, and the 2020 model with 94000 km sold for 26250 SAR in September 2023. The 2020 model with 34000 km sold for 31500 SAR in February 2024, but it was in good condition, so it is less comparable. Considering the mileage and condition, the 2019 and 2020 models with similar conditions and higher mileages are more relevant. Next, I reviewed the listed prices of similar cars. The 2021 model with 128000 km is listed for 32500 SAR, but listed prices are generally higher than selling prices. Other 2021 models with lower mileages (103913 km and 92000 km) are listed for 28000 SAR and 28500 SAR respectively. Given the higher mileage and average condition of the target car, I adjusted the estimate downwards from these listed prices. Taking into account the selling prices and the listed prices, I arrived at a reasonable market price estimate.