why don't you make fake or custom cash? like instead of using the euro with the stars around it use little squares or something and in the center using a null simbol like a tree or so, so it doesn't relate to any specific country.
that way you would still be able to tell it was suposed to be a euro (or any other modified coin/paper currency) but it wasn't quite it.
For example the German Euro has a eagle on the back why don't you use a pigeon like this:
http://www.shinwa-kogyo.co.jp/items/birdbye/img/pegeon.gif
nOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOb!