as students, I would actually recommend checking out
www.studentuniverse.com I booked my flights to Germany through them and have not had a problem (knock on wood!) My flights were $420 round trip from Chicago to Frankfurt. I haven't really checked the domestic flights, but these international flights were almost half 'normal' price - and they are on United/Lufthansa so they are not on the no-name airlines - and student univers works with Orbitz.
Just a suggestion
Sarah