Even in the age of PayPal, Square and Bitcoin, many people pull out a green piece of paper to pay for their morning coffee without giving the transaction much thought.
Somebody, though, had to get that piece of paper to your neighbourhood ATM, and you had to spend some petrol or shoe leather to get it out.
Cash also carries a risk of theft, and it allows some unscrupulous people to evade taxes.
Researchers from [The Fletcher School at] Tufts University added up all of those costs and came up with a big number. They say that based on "highly conservative assumptions," the cost of cash in the US amounts to $US200 billion ($A215.04 billion) a year.
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