Thank you Cashew for all these wonderful suggestions #CashtheDEW

Green Energy Grimme Hatte

https://marketplace.tf/items/tf2/383;5;u9

$117.95 on April 22 (https://backpack.tf/item/4439830503) = 67 keys

$119.99 on May 15 (https://backpack.tf/item/4439830503, b/o 70 https://bot.tf/stats/listings/4J91ZOPV) = 63 keys

https://backpack.tf/profiles/76561198363231274#!/compare/1588032000/1588291200

https://backpack.tf/profiles/76561197983558864#!/compare/1587859200/1588291200 bulk

https://bot.tf/stats/listings/MGLK05Q3 b/o 65

https://backpack.tf/profiles/76561198156255538#!/compare/1589587200/1589673600

https://backpack.tf/profiles/76561198363231274#!/compare/1589500800/1589760000 bulk quicksell

https://bot.tf/stats/listings/4J992OGV b/o 74

https://backpack.tf/profiles/76561198335791307#!/compare/1585267200/1585353600

https://backpack.tf/profiles/76561198045968907#!/compare/1584921600/1585353600 green energy universal (37.5) + kwatt virus doctor (20.5) + twatt falkirk (20.5) + buds (3.1). Caps at 74

KWatt Virus Doctor mini

https://marketplace.tf/items/tf2/30043;5;u56

$39 on May 21 = 21 keys

$38 on May 20 = 20 keys

Taking 20 - 21

I'm going to exclude 74 here because of two current sellers at 65 (one for 16 days). There recently were 3 sellers at 70 or below (https://bot.tf/stats/listings/4J91ZOPV, https://bot.tf/stats/listings/M195NNOO).

63 - 67