Answer:
What is bought by the yard by is worn by the foot?
Often held but never touched. Always wet but never rusts. Often bits but seldom bit. To use it well you must have wit.
I am the tool, for inspiring many. Buy me in the store, for not much more than a penny. Don't overuse me, or my usefulness will go.
There is an ancient invention. Still used in some parts of the world today. That allows people to see through walls.
A hole leading in, a hole leading out, we connect to a cavern that is slimy all throughout. What are we?
What is so fragile that saying its name breaks it?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?