Complex sentence: Courses at the NDU iCollege are free for DOD military and civilians and also open to federal agency students, U.S. private sector students, and international students, although non-DOD students must pay tuition.
Split into simpler sentences: Courses at the NDU iCollege are free (no tuition) for DOD military and civilians. Courses are also open to federal agency students, U.S. private sector students, and international students, although non-DOD students must pay tuition.