Para vs. Por
The following link is a pretty good summary of when to use Para and when to use Por
Good link, thanks for sharing it.
I like this one: http://www.spanishnewyork.com/automatic/porpara.php
This is a good video, but they don't have the information printed anywhere. After watching it and their example of getting groceries for the mother, which didn't have a direction, I changed my "it is enough for her" answer to por but then it was missed. It would be nice to see those guidelines in print, preferably in less than a minute without having to watch the entire video.