Backpack.tf Comparison:

Sale 1:

https://backpack.tf/item/7719374286

https://backpack.tf/profiles/76561198838788284#!/compare/1602892800/1602979200

Sold for:

9 Keys

Demoman's Fro (Lime): 40 Ref

Villian's Veil (Lime): 26 Ref

Antarctic Parka (Lime): 35 Ref

3 Strange Counter Transfer Tool: 1.88 Ref (All together)

Decal Tool: 1.66 Ref

2 Desc Tag: 1.55 Ref

4 Untraced Warpaint

All Together

10 keys 38 Ref

Sale 2:

https://backpack.tf/item/7317913577

https://backpack.tf/profiles/76561198308422197#!/compare/1603756800/1603843200

Sold for:

16 Keys

Strange Smissmas Saxton (Purp): 38 Ref

Strange Guillotine: 5 Ref

All Together: 16 Keys 43 Ref

Sale 3:

https://backpack.tf/item/7290352167

Untraced

Marketplace.tf Sales:

https://marketplace.tf/partneritem?sku=31016;5;u111&attrib=bp

Sale 1:

31.70 USD divided by 1.82= 17.5 Keys

Taking Range of 17 keys.