There is increasing talk of the world moving from cash to digital dollars.
Tony Richards from the Reserve bank of Australia says it is possible that Australian dollars will one day come in digital form.
His speech was delivered just days after former US Treasury boss Larry Summers said it was time to scrap the US one hundred dollar bill. He says the $100 bill is the preferred payment method for organised crime.
There are certainly a lot of those $100 bills in circulation - around 10.8 billion of them.
Here is New Zealand there are around $1.8 billion worth of $100 notes. The majority are held in bank vaults, but it is estimated there could be up to ten percent held by individuals.
Economists say that getting rid of cash entirely would make it harder for organised crime to make money. It would also boost the tax take.
But opponents say it would give governments more control over people's lives. They'd no longer be able to store money in a safe or under the bed.