Ok, this time I have solid information.

The price of this hat is fluctuating slowly and the sell orders have changed to be much higher than it used to be, the hat is still pretty valuable for it's price and it's been changing with other people wanting the hat.

Here is some things I have found [wayback screenshots too Incase things change from the time of writing this]

Seller: https://backpack.tf/u/76561198046264916

Listings: https://backpack.tf/stats/Unusual/Noble%20Nickel%20Amassment%20of%20Hats/Tradable/Craftable/57

Wayback stuff

#1: https://web.archive.org/web/20231207161419/https://backpack.tf/stats/Unusual/Noble%20Nickel%20Amassment%20of%20Hats/Tradable/Craftable/57

#2: https://web.archive.org/web/20231207161637/https://backpack.tf/u/76561198046264916

Screenshots and images of people selling the hat for:

https://ibb.co/QmqFGws

How old the prices used to be:

https://ibb.co/5Y03Bx5

Other notes:

The price of the hat when selling has gone up far from the "11" keys the suggested value says, there was a time a bit tried selling the hat for 20 keys which is insane for the hat. A well-known trader is selling the hat for 15 keys which is well above the 11 keys and some other people [including myself] are also selling the hat above the suggestion so I think maybe a suggestion change will be in place for the hat. It also doesn't help that the suggested price is 4 years old so maybe a change could be good for it.