At present, most of the stamps sold at post offices are newly issued mint and sub-mint mint stamps, as well as ordinary stamps sold for a long time, various kinds of annual stamp albums, gift stamp albums, thematic stamp albums, commemorative albums, etc.
The above mentioned stamps and various stamp albums may be found in shops or kiosks at airports, stations and piers.
The above mentioned stamps and various stamp albums may be sold in stores or kiosks at airports, stations and piers.
A variety of stamps can be bought and sold as collectibles at stores and stalls in stamp markets (or coin card markets) in large and medium-sized cities around the country.
On the Internet, most of the stamp stores in the philatelic websites or selling websites have stamps as collectibles for sale.
Even the stores and stalls in the collectors' markets and second-hand goods markets in large and medium-sized cities all over China may have stamps for sale as collectors' items.
So, the current situation is that once the stamps are sold by the post office (or sold on behalf of the post office, etc.) and enter the market, they become collectibles and can be bought and sold freely!