Ok this is to get a stack of mats that someone is selling cheap.
1) Make a bank alt with a generic name. I.E. BnkAllt or something
2) Send him 100g or so.
3) Find someone that is selling a stack of mats. I.E. WTS Void Crystals x7 PST
4) Find out how much the stack is going for. I.E. 275g for the stack
5) Open trade and wait for the person to put the stack of w/e in.
6) Put 27g in the money to be traded slot.
7) Hope he hits trade really fast not realizing he lost money.
Mail the stuff to another alt and then to another bank alt to avoid getting caught.
9) Sell on the AH or wait a couple days and sell in trade.