Chilean Visa (Santiago de Chile)

Hi,
Looking into obtaining a 6 month visa for Chile from US, we are looking at about $ Protected content the four of us! I know that w=one can obtain a 3 month visa upon entering the country, but you have to leave to be able to re-enter with a new visa. Is this true? Can simply drive from Santiago to anywhere in Argentina and re-enter a few days later with a new 3 months renewal? Or should we cough up the couple of thousands and get our 6 month visa here in the US and not risk it? Any advice will be greatly appreciated!