What Am I Riddles

Question: What cannot be seen or felt, but can only be broken by voice?

Question: I have no wallet but I pay my way.I travel the world but in the corner I stay.

What am I?

Question: Every night I'm told what to do,
and each morning I do what I'm told.
But I still don't escape your scold.

What am I?

Question: Those who make this item, don't use it. Those who BUY this item, have no need for it. But those who USE this item, never see it. What is the item?

Question: 500 is at my end and my start, yet 5 is at my heart.
The first letter and the first number make me complete.
My name is that of a king.

What am I?