Keep a few coins or tokens with you at all times by snapping them into this card and then slide it into your wallet like a credit card. 

The STL comes with slots for 2 Canadian toonies, 1 Canadian loonie, and 2 Canadian quarters, since that's where I live, but if you've got Euros, Pounds, or just want to carry a few shopping-cart tokens around, simply change the sizes and positions in the provided OpenSCAD script and you can carry whatever combination you like.