I have spoken to Fastway, they have good prices and a 1kg and 3kg satchel.

The 1kg satchel is pretty small 190mm x 260mm, but will work for me for many things.

They are about $6.11. This I believe is insured as well.
The 3kg satchel is a bit bigger and is $9.49.

Probably only works for me down the East coast.

From where I am in Port Douglas down to Melb and perhaps Adelaide.

I will not use for WA and they do not deliver to the central parts of Aus.

So they will work for a lot of things but perhaps not everything.

Will just be happy when I am no longer totally reliant on the price gouging Australia Post.