Coin Heist.
For those on Netflix, check it out.
In the kids and family section.
It's a movie all about coins (design, manufacture and collection), and goes into the value of mules.
Interesting.
[video=youtube]http://www.youtube.com/watch?v=xUyTRSlmXf4[/video]
Edit: warning. It's a kids movie.
https://m.youtube.com/watch?v=xUyTRSlmXf4