I've been using Arrow Trader Lite for a while, all I can say is I love it. Recently I bought the Pro version. The free version (lite) takes only 0,8% of the traffic going to trades (for example TTT takes 1% of the clicks, which is 3 times more). It is written in C++, and has even more features then many $$$ script. You should give it a try.
http://www.arrowscripts.com