Sample date : Star Alliance DEC 2-7 MIA or IAH - JNB $654 a.i.
BOS-JNB $715 a.i.
IAD-JNB $718 a.i
Lax-JNB $796 a.i.

Many dates available starting in early October.
Bookable on flightnetwork.
maybe a selfi
base fares as low as $113.50 each way...
The other alliances also have very good base fares