Answer:
I dig out tiny caves and store gold and silver in them. I also build bridges of silver and make crowns of gold. Sooner or later everybody needs my help yet many people are afraid to let me help them.
I don't live within a house nor do I live without. Most will use me when they come in and again when they go out.
I can go through glass without breaking it.
I am three simple words everyone wants to hear. Three simple words such simple words and yet...life changing...
I am gentle enough to soothe your skin, light enough to fly in the sky, strong enough to crack rocks. What am I?
A little house full of meat, no door to go in and eat.