Zero approaches the OTC camp, smiling.

"Hey there. Can I do anything for you?"

"We're all set, thanks, we'll be coming forward in the morning to do some negotiating.  Can we get you anything?"

"A drink?"

"Sure."  

*Clue dump: wood coins are used, then copper, silver, gold, crystal with a piece of elemental, then oricalcum coins which are used mostly ceremonial.   There is a movement to use wood coins with the word "gold", but people keep pointing out that this will lead to a bunch of people writing "gold" on little pieces of wood.  OTC uses "cheques" instead of actually carrying around gold.  Eventually, you figure out that this leads to them having lots of money, buying
all your stuff. and then you have the money and they have all the stuff.*

Zero tries to explain with a lot of complex math words how you create gold, and then creates a perfect illusion of a piece of gold which he hands to the OTC rep. 

He bites into it, and it disappears.

Zero tries to explain that his master is a human who likes going
around looking like a 3 ft blue muppet, but that that is irrelevant
because he can trivially create gold coins that are much more
realistic than this one, so it's a horrible idea to base an economy
around something so easily faked.  

"I'm going to have to think about  this for a while... um... yeah" 

Zero--but you could just mind-control people, or bribe them, and make them trade everything they have for a
shiny rock.

"This is why we have police, and mutual defence corps, and don't allow mind-control" 

The OTC guy tries to explain how trade allows people to specialize in what they are best at, and that the OTC
specializes in moving things from where they are produced to where
they are needed. Then he starts to get... offended and says, 

"You, sir, are an Adept.  You may have no respect for my business, but what
I do I wo well, aboveboard and honest with no magic whatsoever. I
would prefer to continue this conversation with someone who doesn't
spend their time learning to brainwash people"