I was thinking along similar lines myself until I hit this....
What if someone kidnaps your flowerpot and sends a ransom demand for $10 (yes, I know it's daft, but stick with me here.)
Would you pay it? Especially if it's from your late mother and it meant a great deal to her - and therefore you?
Personally, I would. And that act would attach a crass monetary value (dammit!) to my 'priceless' object. I guess it's all about finding the right market?
The value question is not what one would pay to get it back but what one would sell to give it away
In your example, the pot was valued at only 10 bucks by the theif. That 10 bucks has NO bearing on the value you place on it