How Do They Do it? - 2013 $10.00 Kangaroo Maxi Card.

Maxicard stamps can be reused.

You can also use a maxicard, no matter what cost is on it, it can be mailed anywhere.

Huckles chipped in "Call me cynical but something doesn't seem to add up"

It doesn't add up, because you are comparing the price with Australia Post.
Someone, somewhere lost out against original purchase price, as most do with items marketed as "collectible"

The vendor on the other hand, possibly picked up the items in a bulk purchase somewhere
where stock was needed to maintain "cash flow", the life blood of a stamp dealer.

My rule of thumb for buying off the internet is 25% of catalogue value,
When I buy and break down a collection, then the duplicates sell for pennies,
but you sell cheap to both recoup monies for the next purchase, and to maintain "cash flow".

There is, a self evident corollary, to that summation BC.

I want to buy at 25% of catalogue, and then imagine the value of my collection at 125% of catalogue. Hehehe

( I miss those cheeky emoticons over at SCF)