To estimate the price of the 2018 Mazda 6 I4 2.5L Core (Base+), I considered the selling prices of similar cars. The closest match is the 2017 Mazda 6 I4 2.5L Core (Base+) with 207000 km sold for 29500 SAR on 2024-04-22. Adjusting for the slightly lower mileage of the target car (192500 km), I estimate a slight increase in value. Another relevant data point is the 2016 Mazda 6 I4 2.5L Core (Base+) with 204000 km sold for 37000 SAR on 2024-04-03. Considering the target car is a year newer, I estimate a higher value. The 2017 Mazda 6 I4 2.5L S (Base) with 155000 km sold for 46000 SAR on 2023-10-09, but this variant is slightly different. Balancing these factors, I estimate the market price accordingly.