The blue "Doge" stamp is already sold out in the online store of the Austrian Post office.

If you translate the German statement, it says: "Sold out in presale. Avalaible again on 25.06.2020.". So there are some stamps left.



Source: https://onlineshop.post.at/onlineshop/briefmarken---philatelie/crypto-stamps/im-presale-ausverkauft-crypto-stamp-doge-700_19633