Frosty!

Sales

Sale 1: Bulk

https://backpack.tf/profiles/76561198160732392#!/compare/1600473600/1600560000

https://backpack.tf/profiles/76561198819747735#!/compare/1600473600/1600560000

Sale 2: Sold with 5 keys for Steaming Exquisite Rack (55 keys)

https://backpack.tf/profiles/76561198153789411#!/compare/1599264000/1599350400

https://backpack.tf/profiles/76561198269384244#!/compare/1599264000/1599350400

55 - 5 = 50 keys

Sale 3: Sold for Burning Flames Head Of Defense (37 keys) + 11 keys + Strange Law (1 key)

https://backpack.tf/profiles/76561198056681334#!/compare/1599004800/1599091200

https://backpack.tf/profiles/76561198153789411#!/compare/1599091200/1599177600

37 + 11 + 1 = 51 keys

Head of Defense: https://backpack.tf/suggestion/5f7bfd8d21ecbb6b5318521d

Sale 4: Untrace

https://backpack.tf/profiles/76561198992879163#!/compare/1594684800/1598572800

https://backpack.tf/profiles/76561198056681334#!/compare/1594598400/1595635200

Marketplace sales

https://marketplace.tf/items/tf2/309;5;u87

August

129.99 on August 7 (129.99/1.85 = 70~)

https://manic.tf/keyprice/?at=2020-08-07

https://backpack.tf/item/8174164942

Current Classifieds

https://backpack.tf/classifieds?item=Big%20Chief&quality=5&tradable=1&craftable=1&australium=-1&particle=87&killstreak_tier=0

https://gyazo.com/604959d87e62431950d22915fd996033

Summary

Sales at 50 and 51.

Marketplace sales at 70.

Conclusion

There are sellers at 50 and 60, showing that 70 is a high outlier here.

Going with 50-51 here.

Take it easy.