50p 100 years of Girl Guides coin

I've come into posession of a 50p, 100 years of girl guides coin. I got it from a relative who noticed it wasn't like normal 50p's, so she's asked me about it, like I know much(!).

Googling, I see them going for between £1 and £2 on Ebay, but I've also seen articles on the net where they've sold for upwards of £800. Is there any reason for this massive disparity? The difference seems extreme.

I think it's a mix out of hype and more money than sense.

It is worth as much as somebody is willing to pay for it. If it says 50 years it is a fake because it should say 100 years.

https://en.numista.com/catalogue/pieces16649.html

If you would like to send me £800.00, I have a spare one.
They might be worth a little more than 50 pence, as they are now becoming a rarer sight in my change.
If it is worth £800.00, then what is the Kew Gardens coin worth?

Quote: "Merv"​It is worth as much as somebody is willing to pay for it. If it says 50 years it is a fake because it should say 100 years.
​
​https://en.numista.com/catalogue/pieces16649.html

​You're right, it's 100 years, I've edited to correct that info.

The £800+ one had some error, link below:

https://www.mirror.co.uk/money/rare-girl-guide-50p-selling-13715161

Also, the Daily Mirror is misinforming you. What they mean is some chancer listed a coin worth 50p for £825