1. Purchase some wrapping paper from an Inn (Sells in Goldshire for sure, and most Inn's)
2. Goto Ironforge or Orgrimmar
3. Goto an Auction House
4. Find an epic thats buyout is for around 200g
5. In trade channel say "WTS [Epic] 150g! Hurry!"
6. When someone sends you a tell saying they wanna buy it, tell them you gotta go and you will mail it to them.
7. Wrap up some crappy weapon in the paper.
8. Send it to your victim.
9. Log on later, and open up your mail. You might just be 150g richer!
This works about 5% of the time (1/20), but, still possible. Its very good to just do this on an alt so people don't trust your main account.
You MAY get a warning/suspention or even a ban (unlikely), use at own risk.