I managed to whittle something worth more than the $10 that they started out at. My sim was lvl 10+ and always in a good mood. At one point, when she had whittled 77 horses, they suddenly went up and up in value, for about 8 horses. I think the highest value one was $20. When she next started whittling again, they were back at 10, and I can't figure out what it was she was doing or where she was whittling, or what might have effected the price change. I have whittled with another sim, my wizard this time, and she has done over 100 pieces all of the same $10 value. I've tried leaving them her inventory to see if they appreciate, but they don't. On reflection, I'm wondering if perhaps she had the 'inspired' buff. Next time I see it, I'll test my theory. I'm determined to pin-point this though!