It's time to check your purse again for the latest coin to be selling for way more than its face value: a misprinted £2 this time.
The coin itself, released in 2007 to mark the 200th anniversary of the abolition of the slave trade, isn't rare: nearly eight and a half million were minted.
However a few of these have a hard-to-spot error. The wording around the edge of the coin - 'Am I Not A Man And Brother' - is printed the wrong way up.
To check your own coins, place them with the queen's head up: if the writing's upside down, then you've found a winner.
Several £2 coins bearing the misprinted message are currently up for sale on eBay with price tags of hundreds of pounds: the owner of this one, for example, is looking for £385.
However, according to the Check Your Change website, there are known fakes of this coin doing the rounds. The back of the coin is of poor quality, the detail to the Queen is inaccurate and some of the dots around the rim are poorly defined or missing.
At least one of the coins for sale on eBay appears to be one of these fakes.
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However, while the list includes a couple of £2 coins that were only released in small numbers, they're worth just a few pounds. It's mistakes such as those on the 'Am I Not A Man And Brother' coin that really bring in the cash.
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Notes, too, can be worth far more than their face value, even when there's no misprint. Earlier this year, when the new polymer £5 note was released, some were changing hands for more than £200, thanks to serial numbers beginning AA01 - or even AK47.
And earlier this month, it was revealed that artist Graham Short has engraved a tiny portrait of Jane Austen on just four of the new £5 notes - which have been valued at £50,000 each as a result.