hi....
this is the price of emirates airlines:
from melbourne to Amman is 1993 Australian dollar
the route is melbourne -dubai- Amman
Form melbourne to riyadh is 1946.90 Australin dolhars.
the route is melbourne - dubai - riyadh.
and you can travel with qantas or malaysian airline to kuala lumpur and then travel with saudia arabian airlines.
or travel with singapoure airlines to singapoure and then travel with saudia arabian airlines.
but in my opinion its better to travel with emirates airlines so you don't get confused by changeing airlines and its direct.
and i wish you good lack with your flight