- Video report by ITV News Wales and West of England Correspondent Rupert Evelyn
Thousands of new £1 coins are in circulation with "major" flaws - including missing middles.
The new 12-sided coins were designed to be more difficult to counterfeit but the Royal Mint has admitted to ITV News that "variances" have occurred in some of the coins.
Warped and broken versions have been appearing on eBay with starting prices as high as £5,000 and some of the flawed coins have reportedly been selling for as much as £2,500.
Shopper Tamzin Nye told The Sun how she found a gap in a new coin given to her in change.
"I just got confused at how it got out really, even if it is a fake it's meant to be an unfakeable pound coin for it to come out so quickly, or however it got out of the Royal Mint," the 18-year-old from Deal, Kent said.
Introduced in late March, there will eventually be 1.5 billion of the new coins in circulation.
Earlier this year coin experts stumbled on a rare minting error in around 3,000 £2 coins that saw the Queen's head cast upside down - giving the coins a value of around £350.
While the mishappen and flawed £1 coins are being auctioned for far more than their intended value, "trial" and "proof" coins are also potential money spinners.
Around 200,000 trial coins were issued to retailers last year for testing and while not legal tender, the coins can fetch up to £250 among collectors.
Proof coins are also worth much more as they have a significantly higher finish than the currency that eventually ends up in circulation.
The “round pound” will stop being legal tender on October 15 this year, while the old paper £5 notes cease being legal tender this Friday 5 May.