I have some 1kg satchels and I would like to use one on the listing I'm currently doing but there is no choice for that in the drop down box on the listing page. What do I do? thanks
You will have to create a new Postage Policy.
Choose Australia Post Flat Postage - then put in 1 kg and enter your price as you would normally.
It won't be under ebay postage as they don't offer a 1kg option.