I bought 6 yesterday and the lady asked me the very same question.
Just can't see myself using 100 of them anytime soon
I don't see myself either, but if you don't use them all you can always just sell them off for like 80cents each and make a bit of cash.
Yep buying all padded bags in boxes of 100 from Auspost works out heaps cheaper if you can afford the upfront cost.
I just reuse old padded bags and package them inside a new C5 envelope which costs $40 for a box of 500 envelopes.
8 cents!
Even cheaper!
Ersk