People sell willows for lowest price > you buy willows > fletch into bow (u) > sell to your ather acc =D
logs = 20 gp
bows (u) = 160 gp
bow - logs = profit
profit = 140gp p log
example.. Your selling an acc for 700k... You buy 100k worth of willows (about 5k).. you then fletch into willow bows (u) and trade them to your buyer for 800k. so you have 800k, take away the 100k you spent on willows = 700k profit =D