So you found a coin? Hang on.... Its worth how much???

The incredibly sought-after Olympic fifty pence piece sold just 10 days after being listed on eBay by its owner. Initially the coin, which entered circulation nine years ago to mark the London 2012 Olympic Games, was placed online in May with a starting bid of just £10. But the bids started rolling in and the seller quickly had 68 bids to contend with, taking the winning bid to a staggering £10,101.

It was listed on eBay as "Very rare 2011 olympic 50p coin With Waterlines On Swimmer Face Not Kew Gardens".

In 2010 and 2011, 29 new 50p designs were released into circulation to mark the 2012 Olympics. This included an Olympics Swimmer coin featuring wavy lines across the swimmer’s face, however only 600 were ever produced before the design was amended to show the athlete's full face.

Original & the Re-design

Six hundred is a tiny amount in the world of coin collecting. To put this into context, there are around 6.7million Battle of Hastings 50p coins in circulation and 2,179,000 Olympic Triathlon 50p coins out there right now. And that's what makes it so valuable.

After the "re-design", when the swimmers face was revealed from behind the water, the Royal Mint rereleased 2,179,000 of these coins, which is a massive increase in the original 600.. With the lowest mintage of any of the circulated "Olympic 50p" being well over 1 million, you can start to see why the original coin become so desirable.

Experts at coin specialists Change Checker predict that these coins could be worth between £1,000 and £1,500.

The seller found the coin on the beach using a metal detector and said they believed that the coin was in fact one of the rare editions:

If you've got one at home, check to see if the water lines cross over the swimmer's face - if they do, you could be on to a winner. Of course, a coin is only worth what someone will pay for it so there's no guarantee yours will sell for as much.

So dig out your old collection, and keep an eye out in your change, you could be sitting on a small fortune.