It can really be a pain in the ass to find old Coro stuff even though when you find it it is often affordable. Doubly so for inserts instead of cards. For example the poker cards here were a Coro insert that probably had around a million circulated as well: www.elitefourum.com/t/kagemaru-himeno-poker-set-mini-binder/32092/1
Sure a massive amount were produced but I spent months with no luck wasting hours searching corocoro and other key terms like appendix finding nothing… Purchased three comics from the correct month, all three were missing appendix. Ended up trading for them instead of trying to find online. I do know someone was able to eventually find a set for themselves for under fifty bucks but there’s a big difference between "if I pay $50 I can get these cards " and.“If I search several hours a week I might find these and only have to pay $50”. I would’ve rather paid more upfront and saved the time.