The U.S. government spends approximately 4.1 cents [1] to produce each $1 bill. It would probably be more expensive to counterfeit it because of the volume, but I doubt it would be more than $1.

[1] https://www.federalreserve.gov/faqs/currency_12771.htm

The US penny and nickel are the only bits of currency we use that cost more to produce than their face value.

I meant the cost of counterfeiting

If I hypothetically set out to create a single fake one dollar bill that can pass for real ... i would have to spend a lot more than one dollar on the materials ro pull it off, surely?

Now let's take that up a notch with the story of Francis Henning, who counterfeited nickels.

https://coinweek.com/a-collectible-counterfeit-the-story-of-...

Granted, a nickel was worth more in the 1930s...but not that much more.

It's illegal to own these counterfeit nickels because it's illegal to own any counterfeit currency, but they pop up from time to time in collector circles. I don't think the Secret Service cares at this point.

It's not illegal to own fake currency. It's only illegal to possess with intent to defraud: https://www.law.cornell.edu/uscode/text/18/472

Probably, but if you want to make a second one you'll have all the stuff right there still.