I was in the Peace Corps in Bamako. When friends visited, I always recommended going through a consolidator for this trip. One that specialises in trips to Africa. Do not buy directly from the airlines or Travelocity!
Cheapest was invariablly Air Afrique JFK to Dakar, with connecting Ethiopian jump to Bamako.
Ethiopian, at that time, was the only cross-African service available. This was in 1988-90.