How closely have you looked at those dollar bills you're carrying around in your billfold or pocketbook? And what do you think they're really worth?
Here are 10 fun facts about the $1 bill, including how many are in circulation -- and how different they might look today if Benjamin Franklin had won an argument.
1. George Washington hasn't always graced them
Though George Washington is the iconic face of the $1 bill, that hasn't always been the case.
Back in 1862, the very first $1 currency featured a portrait of Salmon P. Chase, who was the secretary of the Treasury at time.
And, in the late 1800s America's first first lady Martha Washington appeared on $1 "silver certificates." Today, those notes sell for $1,000 or more.
2. The number 13 is a thing
The dollar bill has never forgotten America's 13 original colonies. The number 13 is featured repeatedly in its design, such as in the 13 stars above the eagle, the pyramid's 13 levels or steps, and the 13 bars on the shield.
In its talons, the eagle holds 13 arrows and an olive branch with 13 leaves and 13 olive fruits.
It may or may not be a coincidence that there are also 13 letters in the two mottos printed on the $1 bill, "Annuit Coeptis" and "E Pluribus Unum."
3. Some bills are 'star notes'
If you pay attention the next time you find yourself with a stack of $1 bills, chances are you'll find at least one with a star printed next to the serial number.
These are known as (surprise!) "star notes." And they're replacement bills.
If a mistake or defect is discovered on a $1 bill after it has been printed, it's destroyed and a new bill is issued in its place, with a star after the serial number.
4. You can track where a dollar goes
Have you ever been curious where that dollar bill in your wallet has been? There's an easy way to find out.
The site will show all the cities, states, and countries where other people have reported holding your bill. And, you'll be able to track its movements as it continues to circulate.
5. The bills have a short life span
Not only does money not grow on trees, but it also doesn't stick around as long as you may think.
The Federal Reserve estimates that the average $1 bill lasts just 4.8 years.
That may not seem like a long time, but $5 dollar bills last only 3.8 years, on average. And, $10 bills tend to last 3.6 years. Coins tend to stay in circulation for much longer.
6. The $1 bill isn't the most common
There are literally billions of dollar bills in circulation: 12.1 billion to be exact, according to the Federal Reserve.
The $1 bill may be the denomation you see most often in your wallet, but it's not the most widely circulated type of U.S. currency.
That would be the $100 bill, the Fed says. Some 12.5 billion of them are floating around out there.
7. They really are 'cheap money'
"Cheap money" usually refers to loans available at low interest rates, but the $1 bill gives that term new meaning.
Each note costs just 5.6 cents to produce, says the Federal Reserve.
Maybe it's fitting that the $100 bill is far more expensive to make — relatively speaking. Each $100 dollar note costs the government a whole 13.2 cents.
8. Your house may be made of money
Where do dollar bills go when they die? They might be all around you and you don't even know it.
When bills become too old and worn out, they are taken out of circulation and are shredded by the Federal Reserve. And then — ironically enough — the old greenbacks get even more green.
The Fed sometimes sells shredded bills to companies that use them in building materials. Recycled currency may be in the shingles on your roof or the insulation in your walls.
9. The $1 bill won't go out of style
While you may see occasional redesigns of other U.S. currency, it's unlikely that the $1 bill will get a makeover any time soon.
Larger bills have been updated to add counterfeiting prevention features, but the government doesn't feel a need to do that with the $1 bill becaue isn't exactly a favorite of counterfeiters.
A section of the annual Financial Services and General Government Appropriations Act even forbids altering the dollar bill's design.
10. Ben Franklin didn't want the eagle
The back of the dollar bill features the bald eagle, a proud symbol of the United States. But if Benjamin Franklin had gotten his way, we'd be seeing a turkey there.
Franklin once explained in a letter that he found the eagle "a bird of bad moral character" because he said it wasn't responsible enough to do its own fishing.
He thought the turkey would be a much more suitable choice. Franklin described it as a "more respectable bird and ... a true original native of America."