To estimate the price of the 2023 Hyundai Elantra I4 1.6L Smart (Base) with 66000 km mileage, I first considered the selling prices of similar cars. A 2023 Elantra 2.0L Smart (Base) with 4000 km sold for 75000 SAR on 1 Oct 2024. Given the 1.6L engine is typically less expensive than the 2.0L, this suggests a lower price for the 1.6L. A 2024 Elantra 2.0L Smart (Base) with 38600 km sold for 65000 SAR on 17 Jul 2024, but it was in average condition, indicating a higher price for a good condition car. The listed prices for 2023 Elantra 1.6L Smart (Base) with lower mileage were 65000 SAR and 62000 SAR, suggesting a market range. Considering the higher mileage of the target car, I adjusted the estimate downward from these listed prices.