Green Energy Das Ubersternmann

Sale 1: 179.99 USD on mp.tf. 1 key = 1.95 USD --> ~92 keys

https://marketplace.tf/items/30097;5;u9

Sale 2: Sold for Burning Flames Halogen Head Lamp (60) + Orbiting Fire Gentleman's Ushanka (17) --> 77

https://backpack.tf/profiles/76561198339104273#!/compare/1520640000/1520726400

Mini Ushanka: 17 keys pure https://backpack.tf/profiles/76561198167641486#!/compare/1519430400/1519516800

Sale 3: Sold for Haunted Ghosts Das Ubersternmann (73) + 8 keys pure --> 81

https://backpack.tf/profiles/76561198339104273#!/compare/1521763200/1521849600aunt

Mini Ubersternmann: Sold together with 10 keys pure for Green Energy Tossl (83) --> 73

https://backpack.tf/profiles/76561198081129776#!/compare/1521763200/1521849600

Sale 4: Sold together with ~2.75 keys for Green Energy Nuke

https://backpack.tf/profiles/76561198050062763#!/compare/1519516800/1519603200

https://backpack.tf/profiles/76561198073839027#!/compare/1519603200/1519862400

Using this on the Nuke

Sale 5: Sold for Blizzardy Storm Merc's Mohawk; nothing was added it seems

https://backpack.tf/profiles/76561198093501381#!/compare/1521849600/1521936000

https://backpack.tf/profiles/76561198073839027#!/compare/1521849600/1521936000

Should be used on the Mohawk. Most of its sales are unseable/untraceable.

Sale 6: Bulk for DBD Pullover

https://backpack.tf/profiles/76561198255610068#!/compare/1518652800/1518739200

Sales at 77, 81, 92.

Young seller at 85. https://i.imgur.com/cd6WvCM.png

Suggesting range from 77 to 92. Only including 92 because it was cash and thereby pure. MP.TF didn't take much time either so another reason to include it in the range.