Even after a (theoretically

I checked TradeBot 4.0 a bit, but did not find a way to "trade for free", like assigning a price of 0 points to items.
My next thought was to assign each item a value of 1 point and define 1 Pyreal coin to be one point. But I did not manage to include coins in the point system.
Did I miss something ? Or is that impossible in TradeBot ?
How about AutoTrade ? Did someone of you already deal with it (the possibility to check bot inventory with web-browser sounds tempting) ?