Starbase Market
The Starbase Market is a peer-to-peer bazaar where players can sell cards and packs to each other. While the medium of exchange is Hive, prices are set and shown in fiat as it is far less variable. There is a 5% selling fee that is removed from the purchase price before it is passed on to the seller.
A great video tutorial on using the market by @slabakbg is available here.