Coins are common and the majority of us probably have a collection of coins somewhere in our home, whether that be a spare coins jar or just in the pocket of your jeans.
It is worth keeping an eye on your loose change though, as recently a number of rare coins have been selling for eye-watering money.
The reason why they sell for so much is usually because of several reasons, they could've been released for a limited time, may celebrate a certain period of history or they may have a "minting error".