How does a money order work? Where does the cash go and how does the receiver get the cash?

Say i bid and won something on ebay that was $100. If i go get a money order (also can anyway tell me options as to where to get a money order besides a bank and USPS but is there anywhere else?) do i pay the $100 to the guy i got the money order from?

How does a money order work? Where does the cash go and how does the receiver get the cash?
It is exactly like any other business. When you buy that money order for $100.00 it costs you a percentage. Like a 100 U pay $$ extra. That way the people selling you the money order keeps that extra. How simple can we get?

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