How many points is an ork nob worth?

Uhhh.... None? You have to have at least 10 in a unit, so.... One by itself would be worth little since it is unusable. Now if you were to sell it to an Ork player it might be worth something. Is it new on sprue? Is it painted? If so, how well? Does it have the base? What weapons does it have? Is it metal or plastic? The answer to these questions will vary the amount it's worth. Somewhere between $1 and $3 on ebay. Till you subtract for shipping I'd say it isn't worth the effort to sell it.