Trading guilds maintain trading kiosks in cities throughout the map where it's members can sell their wares to the general population. The most popular kiosks are in Rawl'kha in Reaper's March and in the 3 capitols. (Elden Root, Wayrest, and Mournhold) They are bid on weekly on Sunday night. The larger ones tend to be full of active members (most of the bigger trading guilds have inactivity polices and many have minimum sales requirements because bidding on guild traders can be quite expensive) are often quite social, I am in 4. it is not unusual to see members asking for PC's (price checks) in guild chat and if you are on PC, other members responding with M.M (Master Merchant addon) prices. Many trade guilds have social events besides offering guild traders, including raffles, auctions, trivia contests, hide and seek games, trials runs, etc. Many of the players in trading guilds are long-time players and can be a good source of info on the game for newer players, don't be afraid to ask any questions you have in guild chat.