am going to S America for 6 weeks in the Summer. Can anyone who has been help me get the ball rolling. would be really helpful if you could tell me

1) where you would recommend going
2) how much flights are (roughly)
3) which are the cheapest countries to get too?
4) which are the cheapest countries to live in?
5) any general info / tips

anything would be so useful. i don't know where to start!! ideally i want to go somewhere hot (though i know it's not officially their 'summer'), reasonable living costs, not too expensive to get there or around, and with options to go to other countries...
??