The Bureau of Engraving and Printing sells them through the official government website, priced above face value as collectibles. Every note can be cut out and spent. Handing the whole sheet to a cashier is also valid, though they will silently curse you.
Credit: JFitz717
I don’t know what limits you have on coins, but use as many as you can instead. The bills are priced above face value but the coins aren’t and they’re usually heavier.
When I worked at a grocery store, there was a guy who paid for his purchase with a bag of quarters, and had to spend several minutes counting and checking the amount.
So unless you counted them out beforehand, you’d also be inconveniencing yourself (and the other people in line)
It is a funny bit, though
I thought there was a dude who tried to malicious comply in pennies and the payment got rejected. I wouldnt think that would be possible with these bill sheets since it’s not onorous to count.