Dark Forge.

"And as I walk through the valley of the shadow of death..."

Sale: https://backpack.tf/profiles/76561198101092551#!/compare/1528934400/1529020800

Last suggestion will expire soon, so figured I'd get a head start. 1 of 1 since 2016. Guessing either scammer-locked backpack or deletion. Likely the first.

Sold for a Strange Cloud 9 Bomber Knight (in-date price at 125-135, no mini required), FoD Bad Pipes (using my own mini for this one, outdated) and negligible sweets.

The Bomber: https://backpack.tf/suggestion/5b0dcabecf6c756f5b4fe507

Using 130 for this one.

The Taunt:

https://backpack.tf/profiles/76561198101092551#!/compare/1528848000/1528934400

https://backpack.tf/profiles/76561198059796593#!/compare/1528761600/1528934400

Outdated at 10.5 keys. Compares are, once again, screwed up. Even on both ends of the trade. Using this: https://i.imgur.com/lhnYrXG.png (credits to Le mont)

6 keys pure.

Automatic seller for 7 keys: https://backpack.tf/stats/Unusual/Taunt%3A%20Bad%20Pipes/Tradable/Craftable/3005

So, we now have 136 keys. Seller's B/O was 140 keys. This seller was a broker, as I am told by the previous seller. The previous seller was looking for the equivalent of 150 keys on Marketplace.tf before entrusting the broker with the hat.

Rounding to 135 keys.