Big range but based on recent sales, buy orders, and sell orders.. This is what seems just.

Item 1:

https://backpack.tf/item/13308462351

Sale 1: 280 keys pure

https://backpack.tf/profiles/76561198022330462#!/compare/1712102400/1712188800

Sale 2: 490 keys pure

https://backpack.tf/profiles/76561198031126990#!/compare/1714435200/1714521600

Other sale is too old to be used

Unsolds:

500 - https://backpack.tf/item/13517152252

Given that these two sales are both "recent" enough to be used as prices,

just taking 280-490 as the range.

Buyers @ ~232 at the time of suggestion, so lower than the lower bound.

https://imgur.com/a/i4NGJpI

I don't really have methods of finding the other two or three Celestial Starburst Hat Outta Hells, so I may have missed movements. Though, I could imagine that they would also fall within this wide of a range