To estimate the price of the 2016 GMC Terrain I4 2.4L SLE (FWD) (Base) with 135000 km mileage, I first looked at the selling prices of similar cars. The most relevant data points are: a 2016 model with 179000 km sold for 30000 SAR on 2024-06-28, and a 2015 model with 204000 km sold for 21500 SAR on 2024-01-11. The 2016 model is closer in year and mileage, so it is more relevant. Next, I considered the listed prices of similar cars. The most relevant listings are: a 2016 model with 135000 km listed for 36000 SAR, a 2016 model with 119000 km listed for 37000 SAR, and a 2016 model with 179000 km listed for 33000 SAR. These listings suggest a market range of 33000-37000 SAR. Given the actual selling prices and the listed prices, I estimate the market price to be slightly lower than the average listed price but higher than the lowest selling price, considering the car's condition and mileage.