Any time after you have finished the tutorial in the imperial sewers at the start of the game, you can kill a specific person and loot unlimited amounts of gold from them. Here's how you do it:
In the Imperial City, Talos district, find a house owned by a person named Dorian, it will be called "Dorian's House". Try to get him angry enough with you via threatening him. Once he has a low enough disposition (lower than 20) with him, he will ask you to leave. At this point kill him and go to loot his body. He should have around 40 gold and some other misc items. LOOT ALL THE ITEMS FIRST leaving the gold, DO NOT LOOT ALL. When you go to take the gold, it will glitch and keep allowing you to take the gold off him. Make sure he doesn't leave or alerts any of the guards and save before attempting this. After about an hour of hitting the same button, I had 150k gold.