If it's a heap of them in one sale, just put them all in a bubble mailer/tough bag/satchel and send them as normal parcel post. Unfortunately Australia Post (and the others e.g. Mailman) is a ripoff when it comes to sending very small items like these (Coles Little Shop items, or those fruit things they used to have e.g. Billie Banana, that are ever-so-slightly more than 2cm thick are another annoyance). I have the same problem when it comes to posting games - while DVD cases *just* fit in a padded bag (don't use the AP 146mm ones though because they are too small and it's a pain to get them out if they are forced in one), PlayStation 1 and clear-cased DS games games have slightly thicker cases which come out at 22mm when packed.

I have seen many people cheat the system though by simply putting on 2 stamps and hoping it makes it through, usually AP only gets nasty if it's way over the large letter size, but if it's a really small item thrown in a red box rather than at the counter, 99% of the time it doesn't get checked. This can be verified by how many items you receive don't even have the stamps postmarked.

That said, if it does get returned to you complete with a small fine due to "underpaid" postage (according to AP at least) or the seller has to pay the extra to keep their item, you will have to expect to refund them and/or cop a negative and/or low DSRs.

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@bubblebooks2020 wrote:
I bet Australia Post hate that, as things bigger than 2cm can get caught in their sorting machines. 

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What goes through the sorting machines generally depends on the packaging, because they can only handle flexible articles.

 

If sellers use a paper envelope, Aus Post assume the contents are flexible (like it just contains paper documents or similar), and use the machines, if you use a bubble bag, they are usually hand sorted. (I say usually because - despite their own policies of requiring articles to be flexible for the machines - I've seen one of the pre-paid domestic letter with tracking envelopes, which are kinda flexible but still made from relatively rigid card, all torn up from being put through one). 

 

If you use a flat, rigid envelope like their CD mailers, or a generic one, it will definitely be hand-sorted. 

Last time the Coles mini's were here I bought some to complete a couple of sets and I was hit with $7.60 on some because they exceeded large letter specs.

Lucky the sellers were obliging when I sent them pics of the envelopes with underpaid stickers.

 

I am guessing the same is happening now, we just don't hear about it.

The only rare one is the fluffy, only 100 of them available, selling for $5000 to $10000. The blue one isn't rare, even though people say it is.