What is the value of a 2004 Louisiana Purchase nickel with the back printed upside-down?
The value will be five cents. Older coins were often struck with one side first, then the other - meaning that the face and reverse sides were not aligned. Modern processes are able to strike both sides simultaneously - meaning the images on both sides of the coin are perpendicular.
A billion dollars considering that such a coin doesn't and can't exist. US nickels were first minted in 1866, prior to that the 5 cent piece was a tiny silver coin called the half dime. You probably have a Louisiana Purchase commemorative nickel. If you turn it over, you'll find the minting date - 2004 - is on the front of the coin.
It's an ordinary circulation nickel from the Westward Journey series, issued in 2004-2006 to commemorate the Lewis and Clark expedition. Hundreds of millions were struck so they're not rare. If you found it in change it's only worth five cents. Uncirculated or proof-condition ones might retail for $1 to $4 depending on how nicely struck the images are. A lot of people see the 1803 date on the back and mistakenly think that's the year…