Halloween Update was October 1, so skipping any trades before that

Unusualified, you can tell by the date (transactions before October 1):

https://backpack.tf/item/9166754358

https://backpack.tf/item/8389445056

https://backpack.tf/item/6600969682

https://backpack.tf/item/6484549320

https://backpack.tf/item/6468237782

https://backpack.tf/item/6458684848

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https://backpack.tf/profiles/76561198425714292#!/compare/1602720000/1603929600

https://backpack.tf/profiles/76561198143789627#!/compare/1604016000/1604102400

https://backpack.tf/item/9410359263

Untraceable SCM sale

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https://bot.tf/stats/item?def=30919&q=5&ef=Veno%20Shock&craft=1&aus=0&ks=0&source=browser_script

https://gyazo.com/98176d2834e1d285552b4d4e1df95df4

bot.tf nothing

//

https://backpack.tf/item/9247492342

https://backpack.tf/profiles/76561198078552523#!/compare/1602460800/1602547200

https://backpack.tf/profiles/76561198421717954#!/compare/1602460800/1602547200

Sold as unique

https://backpack.tf/profiles/76561198421717954#!/compare/1602806400/1602892800

https://backpack.tf/profiles/76561198070173477#!/compare/1602806400/1604534400

Sold as unique then unusualified

//

https://backpack.tf/item/8369985932

tradeit.gg

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https://backpack.tf/profiles/76561198453530349#!/compare/1603843200/1603929600

https://backpack.tf/profiles/76561198291712570#!/compare/1603843200/1603929600

4 keys leaving the 2nd compare link, and 17.33 returned as change

Current key prices are like 56 refined https://gyazo.com/9e6038a2ea84623a86ae047d3a14ac39

Rounding this sale to 3.85 keys

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https://backpack.tf/item/6509094878

https://backpack.tf/profiles/76561198826254247#!/compare/1601942400/1602115200

https://backpack.tf/profiles/76561198075499550#!/compare/1601769600/1601942400

Untraceable

https://backpack.tf/profiles/76561198075499550#!/compare/1601942400/1602115200

https://backpack.tf/profiles/76561198264356928#!/compare/1602028800/1602115200

unique degreaser epic

https://backpack.tf/profiles/76561198264356928#!/compare/1602028800/1602115200

https://backpack.tf/profiles/76561198019257028#!/compare/1602028800/1602115200

9 keys and 10 refined

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https://backpack.tf/item/6499577142

https://backpack.tf/profiles/76561198341018339#!/compare/1603670400/1603929600

https://backpack.tf/profiles/76561198799503871#!/compare/1603929600/1604188800

12 keys

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https://backpack.tf/item/6485256860

Bought from scrap and unusualified

https://backpack.tf/profiles/76561197991477148#!/compare/1604707200/1604793600

https://backpack.tf/profiles/76561198066311459#!/compare/1604707200/1604880000

Included as part of a bulk/marketplace trade

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https://backpack.tf/item/6484549320

https://backpack.tf/profiles/76561198858685510#!/compare/1602460800/1602547200

https://backpack.tf/profiles/76561197963500354#!/compare/1602460800/1602547200

6 keys and 23 refined

https://backpack.tf/profiles/76561197963500354#!/compare/1602547200/1602633600

https://backpack.tf/profiles/76561198074325951#!/compare/1602288000/1602892800

This is the October 16 Marketplace sale

https://marketplace.tf/items/tf2/30919;5;u3045

October 16 - $29.7 / $1.88 = 15.80 keys

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https://backpack.tf/profiles/76561198045723808#!/compare/1602115200/1602460800

https://backpack.tf/profiles/76561198850121720#!/compare/1602028800/1602115200

Sold as unique, so the next transaction is unusualified

https://backpack.tf/item/6463427275

//

https://backpack.tf/item/6459146281

currently resides in marketplace

//

Sales:

3.85

6.5 ish

9 keys + 10 ref

12

16

Sellers

https://gyazo.com/39d520e8540227a2e58c86c9ebc984ce

3 at $30 / $1.75 = ~17 keys

https://gyazo.com/83bb7a8a10c4ddc84f593bedf3253118

1 seller at 14 keys, 1 month old

16 is high then

buyers at 5.3 keys

9 keys 10 refined is a same day sale

6.5 ended up selling for 16 on marketplace quite fast, and was bought by a reseller too

so maybe just 9-12 keys?