In New Zealand our lowest denomination note is a $5 note.
For perspective, a can of coke costs $1.50 - $2.00, a Big Mac costs around $5.
The idea of a $5 coin is on the cards.
The question is - what effect does turning a note in to a coin have?
I imagine there would more of a piggybank effect (coins being lost, stuck in collection jars).
Are there any studies on what's happened when notes have been replaced by coins?