Very simple, takes a bit of time (a day at the most, an hour at the least).
Idea: You get a letter from Cuergo. Upon opening you see a note and an item with the name of "Cuergo's Hidden Treasure" with a 10 gold COD on it. You take it only to find out its filled with some greys an some ale.
The takedown: Make a toon named Cuergo on your server, if the names taken already (wasn't on mine..) then put an accent mark about the u, e, or o. Go buy (or make) a Cuergo's Treasure Map (wow.allakhazam.com/db/item.html?witem=9254). I got mine for 1g on the AH. Next complete it, takes about 5 minutes... take the Hidden Treasure, but DO NOT, take everything out of the box. What you leave for your victem is up to you, but there needs to be at least 1 thing in the box still. Send the box to your alt named Cuergo, and put a 10g (or whatever you want..). In the Subject leave the name Cuergo's Hidden Treasure, and attach this into the note:
Ahoy [Victems Name]. I be seein' that ye be havin' found me booty map. Be ye supprised when ye came t' come across thar be nothin' at th` wreck site? Figgures...
I felt bad so me an' th` rest o` me buccanneer buddied be havin' decided t' send ye th` real chest. Oh come on now, nothin' in Azeroth be free! Bah! I be thinkin'.. me buccanneers chest here tookst about a voyage o` work, sailin' through th` Malestrom, an' into th` Twistin' Nether, so th` only fair price I could come across be ten dubloon pieces.
Enjoy [Victems Name],
Cuergo, th` One eye`d buccanneer
After that, send away and wait for the free gold
So far I've made 10g (only done this once) but its worked and way.. way to easy.
Note: I made up that shity RP story and found some english to pirate (honestly.. who makes these things??) translator... Feel free to edit it however you like.