It costs the same to print your own Australia Post Labels on eBay as you would pay over the counter.  It is just so much more convenient.  The tracking number is automatically uploaded to eBay, and I can get any number of people to just drop it into the Post Office for me, and bring back a receipt.  All you need are a tape measure to measure the box and a decent set of scales.  Postage can be cheaper having a MyPost account with Australia Post, but you need to sell volumes, not for me, as I am only cleaning out the house of unwanted items.