Finally, you can sell rare coins on eBay. 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.

And in fact, it's worth looking out for any 50p coins that commemorate the 2012 Olympics in London, with Wrestling, Judo and Triathlon designs all following the Football 50p on the Royal Mint list ...

This includes designs for the specific sports, in order of rarity, Football, Wrestling, Judo, Triathlon, Tennis and Goalball. Just 1,125,500 of the Olympic Football 50p coins were minted in 2011 ...