Trade chat can be spammy as hell but I do find some of my best deals there when I can manage to sift through the junk.
I use trade chat to buy items to flip (like battered hilts) find new suppliers for cheap bulk herbs/gems on a consistent basis and also find desperate sellers/buyers who'll pay double price or sell for really cheap.
Unfortunately trade chat only works in town, but with the addon tradeforwarder you can <a href="http://www.wowconfidential.com/wow-a...r-addon/">view trade chat in any zone</a> like BG's, Arena, Raids etc.. so you won't miss any gold making opportunities.
Given the nature of how the addon works, by broadcasting the trade chat from people who have the addon installed currently in town to others in different zones, it becomes more useful the more people who have the addon. So help me spread the word!
you can download the addon over at curse: <a href="http://wow.curse.com/downloads/wow-a...eForwarder</a>