Those new plastic tenners everyone has been going on about have finally entered circulation and, as is very often the case with these sorts of things, some of them are worth much more than their intended value.
Collectors have already been snapping up notes with certain serial numbers on eBay for thousands of pounds, but how do you know if yours is worth something?
Each plastic tenner features a portrait of Jane Austen a quote from her novel Pride and Prejudice that reads: "I declare after all there is no enjoyment like reading."
Serial numbers beginning with 'AH' are becoming popular with collectors and one such note that also had the number 1775 - the year of Jane Austin's birth - recently sold online for a whopping £3,600.
Credit: eBay
Whereas 'AA01' was the serial number prefix to look out for on the plastic fivers, 'AH' is most definitely the one you'll need if you want to make some money.
Many of the 'AA01' notes from this release have gone to charity auction, but nots with the 'AH' prefix have been selling for £30 a piece ever since the new tenner's debut.
However, a few 'AA01' notes have emerged, selling for around £250 each.
You'd also be wise to look out for other things to do with Jane Austen, if the £3,600 note is anything to go by. Keep an eye out for 'JA01', they're Austen's initials; 'JA75', because that's Austen's birth year; and 'JA17', the year of the author's death.
Change collecting website and blog, Changechecker.org, writes: "Whilst these will likely become popular with collectors in the future, it could be many years before notes with these serial numbers enter circulation due to the huge amount of possible combinations that would come before 'JA'."
The new polymer notes entered circulation last week and join the plastic five pound notes, as older paper bank notes gradually get phased out.
Credit: PA
Bank of England governor Mark Carney said: "The new £10 note celebrates Jane Austen's work. Austen's novels have a universal appeal and speak as powerfully today as they did when they were first published.
"The new £10 is printed on polymer, making it safer, stronger and cleaner.
"The note will also include a new tactile feature on the £10 to help the visually impaired, ensuring the nation's money is as inclusive as possible."
As for the old tenners, you can continue to spend them for now, but they will be phased out gradually and will eventually be withdrawn in spring 2018.
Featured Image Credit: PATopics: UK