Individuals can list their items for sale in these marketplaces.
Colectalia
Spain
https://www.colectalia.com/en/market
Delcampe International SPRL
Belgium
https://www.delcampe.net
eBay
USA
https://www.ebay.com
eBid
UK
https://www.ebid.net
Hipstamp
USA
https://www.hipstamp.com
OldBid
USA
https://oldbid.com
OneBid
Poland
https://onebid.pl
Philamart
India
https://www.philamart.com
Playle
USA
https://www.playle.com
ricardo.ch SA
Switzerland
https://www.ricardo.ch
Stamp Den
USA
https://www.stampden.com
Zoconet SL
Spain
https://en.todocoleccion.net