darkSpyro

This is a very simple process, and you do not need much to do it. Here is what is necessary to accomplish the trick:

1) You need to have beaten the game.
2) Hopefully you can back up your save data somehow (like a USB flash drive), otherwise be careful

Now, as anyone who has beaten the game likely knows, the crane area has approximately 6-8,000 gold on it after defeating Kaos. If you pick up the gold and leave the arena, of course the game auto-saves you having had the gold, and it won't be back when you log in--all you'll see at the crane is a single stack. In game terms, this is very easy to trick, because autosaves are triggered by swapping zones in Skylanders, and the game will never know you had all that gold if you do a hard exit before re-entering the ship. That being said, here is the method.

1) Enter crane area, grab gold. Since gold is obviously saved to the figure, you will retain it after exiting the game.

2) Do a hard exit. On PS3, this means selecting "Quit Game" from the PS menu, accessible by pressing the PS button on your controller. On Xbox 360, same thing, but with the X-Media Bar and Xbox button respectively. If you're on the Wii, press the Home button in the center of the Wiimote and exit the game.

3) Re-load Skylanders Giants and your save. All 6-8,000 gold will be back at the crane, for a new character to grab.

4) Repeat steps 1-3. Infinite, quick money.

Now, remember the part where I said it might be nice to back up your saved game? If you have a USB, or cloud storage on your system, send a copy of your Giants save file there. The reason why is, even knowing that it's strictly off limits for the purpose of the trick, it is still easy to accidentally leave the crane area and cause the game to save the fact that you were just up there looting all that gold. It's happened to me, it's happened to Vhraina; it can happen to anyone.

EDIT: Oh, and one final tip. Make sure your +Treasure Luck-O-Tron wheels are active, because they make a big difference. You'll get far more 8,000+ gold runs with them than without.