Hi, I searched, but couldn't find the answer in the forum.
So here is my question:
1)Do we have to (require) purchase a round trip plane tix? Or can we just purchase an One way plane tix?

2) If so, when I tried to purchase a round trip tix on orbitz.com, etc, I had to decide a return date. Which date do most students choose? And is there any way to purchase a round trip tix on the internet with an Open date? Or, if we want an open date, do we have to call the airline and purchase them that way?
And an open date plane tix costs more, right? And how long will it be valid?

Thanks~