Sale 1:

https://backpack.tf/profiles/76561198836483281#!/compare/1587427200/1587600000

https://backpack.tf/profiles/76561198367892937#!/compare/1587513600/1587600000

https://backpack.tf/profiles/76561198179584474#!/compare/1587513600/1587600000

https://backpack.tf/profiles/76561198354083970#!/compare/1587772800/1587859200

Untrace / bulk

sale 2:

https://backpack.tf/profiles/76561198354083970#!/compare/1587859200/1588118400

https://backpack.tf/profiles/76561198143708835#!/compare/1587859200/1587945600

Untrace

sale 3:

https://backpack.tf/profiles/76561198143708835#!/compare/1587859200/1587945600

https://backpack.tf/profiles/76561198101915413#!/compare/1587772800/1587945600

Sold with GE Tailor for Mallard Warmer + negligible sweets

sale 4:

https://backpack.tf/profiles/76561198101915413#!/compare/1588377600/1588464000

https://backpack.tf/profiles/76561198071499832#!/compare/1588377600/1588464000

Sold for 40 keys (18 used to buy taunt)

Sale 5:

https://backpack.tf/profiles/76561198071499832#!/compare/1588723200/1588809600

https://backpack.tf/profiles/76561198074621436#!/compare/1588723200/1588809600

Sold with HG Tavish(20.5) for burning Tartan Spartan(40.5)

bulk

sale 6:

https://backpack.tf/profiles/76561198074621436#!/compare/1588809600/1588982400

https://backpack.tf/profiles/76561198040186479#!/compare/1588982400/1589068800

Sold for 30 keys

Sale 7:

https://backpack.tf/profiles/76561198040186479#!/compare/1589068800/1589155200

https://backpack.tf/profiles/76561198058753054#!/compare/1587513600/1589241600

MPTF

sale 8:

https://marketplace.tf/items/tf2/30066;5;u35;strange

84.99 / 1.9 = 44.73 keys <--- https://backpack.tf/item/8326601488 | https://bot.tf/stats/listings/Y3WEQKR0 B/O of 45 keys

total sales @:

30, 40, 45 keys

considering Sale 3 definetly ends up supporting 30,

taking 30 - 40 keys.