Here are some exploits that can land you an infinite amount of Gold and Experience. These techniques are sure to be patched, but you can delete game patches if you've already updated your game.

Complete any side quest that does not activate a cutscene when receiving your reward (for example, the "South-Song" Gerralt's Corpse side quest or any "Find And Deliver" side quest), then save the game. Draw your weapon, and approach the NPC. While your character is putting away their weapon to talk to the NPC, rapidly press A to get unlimited money and EXP. You can keep doing this until you move your character. You can repeat this bug as much as you want. -ragingvalheru

While you are in Kirkwall, there is a quest in the chantry called "Sister Plinth's Remains." While returning her remains to her brother, DO NOT MOVE -- this prevents the exploit from working. Just keep pressing the button to turn over the remains and the brother will keep giving you the reward. Note: You find the remains in Darktown in the top right corner of the map. They are surrounded by a bunch of soldiers. -AgensM