To estimate the price of the 2020 Mercedes A250 with 300000 km mileage, I analyzed the listed prices of similar cars. The closest match is a 2020 Mercedes A250 with 130000 km listed for AED 119750 and AED 109750. Given the high mileage of the target car, I applied a significant depreciation. Other 2019 models with lower mileage (e.g., 182000 km listed for AED 110000) also suggest a lower price for higher mileage. Considering the high mileage and the condition, I adjusted the price downwards significantly.