I don't find it so common sense. To me, it might be worth nothing, it might be worth much more. That is the problem with asking "How much is it worth?" There is a correct answer for each person, since each person has their own idea of how much it is worth.
Well, if my $0 is not the correct answer, what is? If I would only pay $3.50 for it, is that not what it is worth to me? Should I not respond with $3.50? How about if I would pay $150 for the object, and I respond "$150", is it then correct? If so, then why is the $150 the correct answer but $3.50 or $0 not? At what price is the correct answer and I should respond?