We rented a car yesterday with Chilean Rent A Car. We got the cheapest car for 24 hours. I added the extra insurance that waives the deductible and the GPS. The total cost was CLP$27,900. We drove from Santiago to Portillo. We then drove to Valpairaiso via a scenic route and back to Santiago. We drove a total of 520km. We paid about CLP$11,500 in tolls and CLP$24,000 in fuel.
The cheapest car is fine. It made it to the top of Portillo without too much concern. It is weak, but will make it. The added insurance is just for peace of mind when driving in a country like this. The GPS...my phone had data everywhere, but the Maps were not accurate. Unfortunately, neither was the Garmin GPS. Between the two we made it work.
Chilean Rent A Car was easy to deal with. They had plenty of cars to choose from and were not pushy about upgrades. I asked them for the two upgrades. There was always someone there that spoke English, so communication was not an issue either. The chip for local tolls was included at no additional cost. We plan to rent a car again in the next week or so and will use them again.