Sale 1:

https://backpack.tf/profiles/76561198304138933#!/compare/1524355200/1524528000

https://backpack.tf/profiles/76561198267189538#!/compare/1524355200/1524441600

Untraceable, not using

Sale 2:

https://backpack.tf/profiles/76561198267189538#!/compare/1523145600/1523491200

https://backpack.tf/profiles/76561198310144372#!/compare/1523232000/1523404800

Untraceable, not using

[Sale 1 and 2 may have just been transferring the item between different backpacks]

Sale 3:

https://backpack.tf/profiles/76561198059209925#!/compare/1522627200/1522972800

Nuts n' Bolts Towering Pillar of Hats + Starstorm Insomnia Nasty Norsemann (22 keys) = Blizzardy Storm Troublemaker's Tossle Cap (31 keys) + 3 keys

-> 12 keys, useable

High range comes from sales of Strange Nuts n' Bolts Towering Pillar of Hats: https://backpack.tf/suggestion/5ade8f0344325a064c082b5d