Money in Fantasy

[Tristyn-of-Arenstar]

When writing fantasy, what do you usually use as money? What is the value of your coins and how do you calculate it? I am currently using 'crowns', gold crowns, bronze crowns, silver crowns... because you know, can't get anymore original than that. Maybe I should translate it to my language to make it sound cooler, but that may be pointless because only one culture speaks that language.....

The value of my crowns is simple:

One gold crown is equal to two silver crowns.
One gold crown is also equal to three bronze crowns.
Therefore, three bronze crowns are equal to two silver crowns.

How do you utilize your forms of money or payment? Do you use trade instead? I use trade just about as much as I use the crowns, maybe more.