COIN experts have revealed the exact year to look out for on a rare 50p coin which can be sold for 20 times its original value.
Those in possession of the rare coin may find themselves in luck, as collectors are selling them on eBay.
The 50ps feature Britannia, a symbolic representation of Britain, and were issued between 1969 and 2008.
However, only 3,500,000 of the 2008-dated coins entered circulation, making them highly sought-after by coin collectors.
That year also marked the final time the Britannia design was used before the Royal Shield design was introduced.
The unique 2008 50p coin is currently fetching around 20 times its original value on eBay.
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One coin collected managed to sell the coin for £9.99 with other ones going for a similar price.
However, it's not the only 50p that is worth a pretty penny.
A coin that featured a unique design sold for a whopping £1,500.
The error "Lines Over The Face" Aquatics 50p fetched the giant sum in a recent auction.
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The error coin is like plenty of others, such as the Lord Kitchener £2 and 1983 "New Pence", which are so valuable due to them being manufactured incorrectly.
The 50p Lines Over The Face error coin sold for £1,500 in a recent auction run by RWB, based in Wiltshire.
Kimberly Day, coin expert from RWB, said: "Only a few hundred examples with this rare design variation are believed to have been released.
"We're delighted that this coin has raised such a sum, it's a fair price for such a rare coin and we believe its value will only increase over time."
The standard Aquatics 50p was issued by the Royal Mint, the official maker of British coins, in 2011.
It was part of a collection released to mark the 2012 London Olympics - with 29 designs representing different sports.
The error coin is so rare, that it can sell for giant sums like in RWB's recent auction - and it's been known to sell for £1,600 in the past too.
How much are other 50p coins worth?
Many coins can be worth much more when sold on eBay as part of a collection.
However, sometimes you'll get better individual prices if another enthusiast needs your coin to complete their collection.
The rare Blue Peter Olympic 50p has been flogged on eBay for £205.
The coin shows an athlete doing the high jump and was drawn by nine-year-old Florence Jackson after winning a competition on the kid's TV show.
Plus, one seller pocketed a whopping £63,000 flogging his Battle of Hasting's 50p too.
So-called 'error coins' tend to be worth a lot too, because there's rarely more than a few thousand of them in circulation.
One 50p that was mistakenly struck twice sold for as much as £510 on eBay because it was rare.
It's not only 50ps either - a rare error 10p coin sold for over 1,000 times more than its face value on eBay in the past.
Likewise, there are several rare £2 coins in circulation which could be worth just under £50.
How to sell a rare coin
You can sell a rare coin on eBay, Facebook, or in an auction.
If you're selling on Facebook, there are risks attached.
Sellers have previously been targeted by scammers on Facebook saying they want to buy a rare coin and asking for money upfront for a courier to pick it up.
But it's a ruse to get money out of you and the courier is never sent.
To avoid this happening, it's always best to meet a Facebook seller in person when buying or selling anything.
Ensure it's a public meeting spot that's in a well-lit area and if you can, avoid using payment links.
Most sellers prefer to deal with cash directly when meeting to ensure it's legitimate.
The safest way to sell a rare coin is more than likely at auction. You can organise this with The Royal Mint's Collectors Service.
It has a team of experts who can help you authenticate and value your coin.
You can get in touch via email and a member of the valuation team will get back to you.
You will be charged for the service though - the cost varies depending on the size of your collection.
You can also sell rare coins on eBay.
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But take into account that if you manage to sell your item then eBay will charge you 10% of the money you made - this includes postage and packaging.
Always bear in mind when selling any rare coin, you will only get what the seller is willing to pay for it.
Most rare and valuable 50p coins
WE reveal the Royal Mint’s most rare and valuable 50p coins in circulation.
Triathlon
Minted in 2011, the Triathlon 50p depicts the same sport which featured in the 2012 Olympics.
There are more than 1,160,000 of the coins in circulation.
With over 200million 50ps circulating in the UK, that makes this coin quite a rare find.
The highest recent sale we've found on eBay recently was £30 on June 21.
Judo
Judo is a popular sport that involves grappling with your opponent.
But despite the design, it's not so easy to get a hold of this coin, of which there are just 1,161,500 in circulation.
The piece was designed by David Cornell after he won a national competition.
It was minted in 2011 and the highest bid we've seen on eBay was for £17.95 on June 21.
Wrestling
Wrestling was one of the first Olympic sports so it's not surprising that it features on one of the 50p pieces.
The 2011 coin was designed by Roderick Enriquez, a graphic designer from Hammersmith, London.
We've seen it sell for as much as £15 online so is worth digging around for.
In recent months, one was sold on eBay for £11.95 on June 18.
Football
Of all the coins created to commemorate the 2012 Olympic Games, the 50p Football is among the rarest.
It features an explanation of the controversial offside rule on it, with 1,125,000 produced.
One sold for £20 on eBay on June 11, although it has been known to go for as much as £75 in the past.
Kew Gardens
The Kew Gardens 50p is the rarest of all the 50p pieces, with only 210,000 in circulation.
They have been known to sell for as much as £895 on eBay before.
The design was created by Christopher Le Brun RA and features the famous Chinese Pagoda with a leafy chamber that twists around the tower.
The coin often sparks the interest of new coin collectors due to its rarity.
The highest sale we found in recent weeks was £142 on June 22 with 23 bids.