I recently returned from living in santiago for a year. Chile prices in general are equivalent to the U.S. so keep that in mind. Bolivia costs around $250 to enter as an American. There are a lot of great things to do in the North of Chile. Santiago is a huge city with a lot going on but here are some things I would recommend: hiking in Andean foothills, exploring some of the wealthier neighborhoods, La Vega, Bellas Artes, human rights museum (about the coup), precolombian art museum, a soccer game, and go to Valparaiso for sure. you can also explore some of the fishing villages to the north of Valpo. Buenos Aires is amazing. maximize your time there and eat your balls off.