Spoilers below... Okay, I am about halfway into the game. I found the actual Stillwater Giant and killed him. I got his pelt. Went to Parnell's to sell him the real pelt. He offers me 2,000. If I say yes right away that's it, 2,000, end of conversation. If I keep saying no and end the conversation I can then talk to him again and "reconsider" selling it to him. He gives me 2,000 gold. I noticed after I sold it that option appears for reconsidering again! So in the conversation options I did this over and over and had like 200,000 gold in a few minutes.
You don’t haft to steal the pelt back? If you want a way to get money and power quickly, buy what ever you want from a wise woman then just Baneful Gauntlet her and you can get all your money back plus interest. After you’ve taken all she has, resurrect her and start to buy more stuff. I think the most gold I ever got was around 300,000.