The coin, a 1981 Queen Elizabeth II 50p coin, features a mis-strike error making it extremely popular with collectors. It inspired a mini-bidding war among shoppers eager to get their hands on the rare Royal Mint coin, with 35 bids placed on the item. (Image: eBay)Eventually, the con was sold for £182.00Five Incredibly Rare and Valuable British CoinsWhat makes a coin valuable? Its 27.5mm diameter makes it the largest of any British coin, and allows space for decorative pictures. Royal Mint top 10 most valuable 50p coinsHere is a list of the top 10 most valuable coins, when they were made and how many were minted: