Seriously though, you’re asking a fantastic question. And, surprisingly, my tongue in cheek response above is sort of correct. The world was actually in a similar position to the one you ask about right after WWII ended. The world was still on fire and most countries had no real currency to spend. So, we loaned them the money to buy our goods (not much of a services economy back then).
Of course, that’s what we know today as the Marshall plan. In it, we gave billions of dollars of aid to other countries to help them rebuild their infrastructure and economies.
But if that ever happened in peacetime (I.e. not right after a war), then that would be very unusual. Maybe after a worldwide depression, but that is usually followed by war anyway.
Great question, and hopefully we never really find out. It probably would be a very rough ride for lots of people on this planet.
[0] - http://www.history.com/topics/world-war-ii/marshall-plan