There's never really a "great" item to merchant, as soon as it becomes popular, and more people merchant an item, then everyone gets this "I r teh mast3r m3kantor" attitude and no one sells or buys for what the other wants. I used to do black cavvies, 900k in game, 1.1mil on forums, and could fo a good 2-6 of them an hour. Now, good luck buying for 1.1mil and selling for 1.101mil on forums. Experiment around, try alil this, alil that. As for coal, buy f2p in medium amounts 150 each (500 works good) Buy a few K worth of coal, sell forums 200 each, only do large amounts, anything 1k or lower people will only keep at 180. 3k and higher you can pull 200 each pretty consistantly.