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 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.
Households pay about $US8 billion in ATM fees and lose $US500 million a year to theft, but the study puts their total cost much higher, at $US43 billion. Most of that comes from assigning a value to the time that people spend going to ATMs or check-cashing stores.
Theft is a much bigger issue for businesses, accounting for $US40 billion of their more than $US50 billion in total cost of handling cash.
The biggest loser in the cash economy is government which, of course, creates the cash in the first place.
Printing and distributing the money costs only $US1.2 billion, but the study estimates that tax evasion amounts to $US100 billion a year.
Men carry nearly twice as much cash as women do, the study found, and people over age 55 hold roughly twice as much as the 35-and-under crowd. The younger group is more likely to incur fees for accessing cash, though. Rich people also tend to carry more cash.
The unbanked poor, however, pay a disproportionate share of the cost of cash.
"The persistence of a cash economy creates social inequity and has the effect of a regressive tax," the study concludes.