Okay. In a nut shell Free Trade means that stuff on other servers that are no trade can now be traded or sold among players.
Firona Vie and Brekt are both "Free Trade" servers. For almost ALL items that on a regular server (Like Xenogy or AB) are marked as "No Trade" will not have the NT tag, and can be sold, traded to other players, either via /Broker, /Bazaar or direct trade. One example off the top of my head would be a Red Dragon Scale off of Naggy. On regular servers, if your warrior is over 51 and hadn't participated in a Naggy raid, then they could only get one off of certain Kunark dragons, Master Yaale, etc. On FV and Brekt, you can buy it off of the bazaar or a player.