Gordon Banks sold his winners medal to stop his children falling out over what to do with it once he has passed away.
He has probably heard of or seen when families fall apart after the death of a loved one, when they fight over who is entitled to what.

Apparently he sold the medal so that the money earned could be split evenly between his children.

In some way there are 'relics' of a bygone age, where the only real proof you played were the medals you had.

Technology has moved on, and any player from the late 80's onwards can easily access recordings etc of major finals, internet reports, newspaper archives etc.

I just don't really understand the value a fan would put on owning it.

Wouldn't you have thought his 'children' would have more sense than to argue over a treasured possesion of their father's so much he felt the need to offload it. They should be ashamed and count themselves lucky that he is still here to pass on his memories of his life and his great career. They should treasure their Dad not his possesions.

was on the news this morning nobby stiles is selling his medal expected to make around £150,000

I can understand selling something that's worth £150,000.

A Challenge Cup loser's medal is hardly going to bring in a life changing sum though so in my opinion it should be given away to a fan or charity to raffle off if it isn't wanted.