Answer:
I am needed for most animals and hardcover books
I am often sold by children entrepreneurs in summer time
I am an instrument capable of making numerous sounds but cannot be touched or seen. What am I?
I save lives on the ground and in the air. What am I?
What has a head but never weeps a bed but never sleeps can run but never walks and banks but no money?
When is it bad luck to see a black cat?