I use the ebay satchels with the ebay labels as it is slightly cheaper and as long as you lodge them over counter and get a receipt you have all the tracking you need. For items over $50 I also add SOD so if it does go missing I can claim from Aus Post as I don't see why I, the buyer, ebay or Paypal should be out of pocket for AP's stuff ups.

If for any reason I can't use an ebay satchel I use my own packaging if it is under 500g as it is cheaper than a plain, AP 500g satchel.

If an item can be packed thin enough I send by letter post, registered if it is more than 20 bucks as that is the most I am prepared to lose if an untracked letter goes missing.

Everything is placed in a ziplock bag so there is less chance of damage if the outer packaging is ripped which does happen.

I have never felt the need, as some do, to justify my delivery charges. I add around one to two dollars on top of the stamp cost per item and my postage cost star is perfectly fine without me having to tell everyone that I am charging for paper, ink, compliment card, plastic bag etc etc..