Thanks to Xergoyf

resugg from: https://backpack.tf/suggestion/6013b63fc7aec8091b429663

https://backpack.tf/item/9458254758

Sale 1) untrace or scm sale.

https://backpack.tf/profiles/76561197964546925#!/compare/1606953600/1607212800

https://backpack.tf/profiles/76561198094329754#!/compare/1607040000/1610150400

https://backpack.tf/item/9441159384

Sale 2) untrace

https://backpack.tf/profiles/76561198212670497#!/compare/1605484800/1607904000

https://backpack.tf/profiles/76561198217734829#!/compare/1605571200/1605744000

https://backpack.tf/item/9387997738

Sale 3) ???

https://backpack.tf/profiles/76561198065601992#!/compare/1605484800/1608249600

can't do buyers compare.

https://backpack.tf/item/9340665375

Sale 4) untrace

https://backpack.tf/profiles/76561198188093413#!/compare/1607558400/1607644800

https://backpack.tf/profiles/76561198073896407#!/compare/1606521600/1607126400

https://backpack.tf/item/9313484929

Sale 5) bulk

https://backpack.tf/profiles/76561198105071091#!/compare/1611360000/1611446400

https://backpack.tf/profiles/76561198869144080#!/compare/1611360000/1611446400

https://backpack.tf/item/9294017051

Sale 6) bulk

https://backpack.tf/profiles/76561198296942562#!/compare/1608422400/1608508800

https://backpack.tf/profiles/76561198038666068#!/compare/1608422400/1608508800

Sale 7) untrace

https://backpack.tf/profiles/76561198050518375#!/compare/1609200000/1609286400

https://backpack.tf/profiles/76561198296942562#!/compare/1609200000/1609372800

Sale 8) 8 keys matches

https://backpack.tf/profiles/76561198050518375#!/compare/1611619200/1611705600

https://backpack.tf/profiles/76561199100906514#!/compare/1611532800/1611619200

Sale 9) untrace

https://backpack.tf/profiles/76561198180523995#!/compare/1611532800/1611705600

https://backpack.tf/profiles/76561199100906514#!/compare/1611619200/1611705600

https://backpack.tf/item/9292885004

Sale 10) I bought it for 19 keys. https://prnt.sc/ztihe6

https://backpack.tf/profiles/76561198849751643#!/compare/1611446400/1611532800

https://backpack.tf/profiles/76561198095254789#!/compare/1608249600/1611619200

https://backpack.tf/item/9292885004

Sale 11): Sold it for 25 keys. https://prnt.sc/ztillh

https://backpack.tf/profiles/76561198849751643#!/compare/1611964800/1612051200

https://backpack.tf/profiles/76561198030113816#!/compare/1604188800/1612051200

https://backpack.tf/item/9292231578

Sale 12) bulk

https://backpack.tf/profiles/76561198819747735#!/compare/1608854400/1608940800

https://backpack.tf/profiles/76561198123373965#!/compare/1608940800/1609372800

Sale 13) 21 keys

https://backpack.tf/profiles/76561198144430577#!/compare/1611532800/1611619200

marketplace.tf sales: https://marketplace.tf/items/tf2/31128;5;u158

$59.99 / $2.12 = 28.30 keys

$55 / $1.79 = 30.73 keys

gladiator.tf stats: https://prnt.sc/xsp52i

https://gladiator.tf/sales?item=Plum%20Prankster%20Hollowed%20Helm

classifieds: https://prnt.sc/xsp8m6

Total sales:

18

19

21

23

24

28

31

lets go with 21-25