For the reasons of economy, I normally use Transdirect which is a shipping aggregator offering services of all major couriers operating in Australia. For more urgent or sensitve shipments I select TNT and their Technology-Sensitive Express Service.
All shipments from me are fully insured and I ask my clients to also insure items sent to me.
The cost of shipment of an average CD player to the major centre on the East Coast is about $25-$30 each way. or double that if TNT is selected as a carrier.