Resuggesting, thank you Xergoyf.

Sales

Sale 1: Sold for 50 keys

https://backpack.tf/profiles/76561198061489334#!/compare/1601769600/1601856000

https://bot.tf/stats/listings/Y96ZJGD0

Sale 2: Sold with 6 keys for Galactic Gateway Hephaistos' Handcraft (39 keys)

https://backpack.tf/profiles/76561198036203563#!/compare/1599609600/1599696000

https://backpack.tf/profiles/76561198061489334#!/compare/1599609600/1599696000

39 - 6 = 33 keys

Sale 3: Sold for 35 keys

https://backpack.tf/profiles/76561198109149008#!/compare/1599091200/1599609600

https://backpack.tf/profiles/76561198036203563#!/compare/1598832000/1599177600

Sale 4: Sold for Strange Wicked Wood Berlin Brain Bowl?

https://backpack.tf/profiles/76561198015668332#!/compare/1594339200/1596153600

https://backpack.tf/profiles/76561198109149008#!/compare/1594684800/1596067200

Sale 5: "Added a C9 Coni Cap (~14) for a Bees Flamehawk (~30 given current sellers) + 4 keys"

https://backpack.tf/profiles/76561198153675141#!/compare/1600300800/1600646400

"20~. Flamehawk was probably more at the time of the sale but eh."

Sale 6: Sold for 27 keys

https://backpack.tf/profiles/76561198153675141#!/compare/1601164800/1601424000

Marketplace sales

https://marketplace.tf/items/tf2/388;5;u13

Nothing recent.

https://marketplace.tf/items/tf2/388;5;u13;strange

August

130 on August 19 (130/1.79 = 73~)

https://manic.tf/keyprice/?at=2020-08-19

https://backpack.tf/item/702591782

September

129.99 on September 5 (129.99/1.83 = 71~)

https://manic.tf/keyprice/?at=2020-09-05

Current Classifieds

https://backpack.tf/classifieds?item=Berlin%20Brain%20Bowl&quality=5&tradable=1&craftable=1&australium=-1&particle=126&killstreak_tier=0

https://gyazo.com/0e313d876ae57899e3bdb59b575e200a

Summary

Sales at 20~, 27, 33, 35, and 50.

Conclusion

"Worth noting that the one who sold for the Bees flamehawk was the one who bought for 50 pure. My guess is that he regretted selling his, and impulse bought one ones on the market, not really concerned with how much it was gonna cost."

Due to this, going to exclude 20 and 50.

27 is probably a quicksale as well, excluding.

Going with 33-35 here.

Take it easy.