Cost of border crossing in rental car, Chile-Argentina-Chile [closed]

My friend is soon going to Chile (from Spain). She wants to rent a car and make a trip into Argentina. One website tells her she has to buy a border-crossing permit for $6 and another says $200.

Seems to me that the website providing the information won't help determine whether the information is true or not. She's not stupid; if it could be determined by the website, she wouldn't have asked.

However, I did a bit of looking. https://www.journeylatinamerica.co.uk/travel-inspiration/ask-the-experts/can-you-cross-the-border-between-chile-and-argentina-in-a-hire-car suggests that the $200 quoted by the Chilean company is a government fee that Avis failed to mention.

https://www.tripadvisor.com/ShowTopic-g294266-i977-k2610925-Border_Crossing_in_a_Rental_Car_Argentina_and_Chile-Argentina.html makes me think the six bucks Avis suggested is a fee for the letter and/or the etching, and if she goes to them, she'll be turned back at the border for the lack of the permit.

So, to reword the question, what's the full story on fees and documents for taking a rental from Chile into Argentina and back?