Answer:
It is everything to someone, and nothing to everyone else. What is it?
What has hands but can't clap?
There is an ancient invention. Still used in some parts of the world today. That allows people to see through walls.
What is the smartest letter of the alphabet?
What do call a dinosaur without gold?
Of these things - I have two. One for me - and one for you. And when you ask about the price, I simply smile and nod twice.