Because breeding scorpions is fun
Most people can't handle keeping whole broods of scorpions, and so usually sell some or all of them.
The most common way to sell surplus scorpions is via the internet. Are there any Aussie scorpion/reptile/exotics forums that have a classifieds section? When you are ready to let some babies go, advertise them on there. You then arrange for the buyers to come and collect them, or most commonly, you post the scorpions to them, especially in a country like Australia where the next city may be 1000 miles away haha.
The other option is to see if your local reptile shop will buy them off you, or give you store credit for them.
Good luck breeding them, or waiting for them to get pregnant, depending on which species you've got
