Sale 1:

https://backpack.tf/profiles/76561198006544512#!/compare/1534204800/1534291200

https://backpack.tf/profiles/76561198089862063#!/compare/1534291200/1534723200

Sold for 18 keys

Sale 2:

https://backpack.tf/profiles/76561198089862063#!/compare/1534723200/1534982400

https://backpack.tf/profiles/76561198257701328#!/compare/1524960000/1534982400

Sold for TW Pomade

Use there.

Sale 3:

https://backpack.tf/profiles/76561198257701328#!/compare/1524960000/1534982400

https://backpack.tf/profiles/76561198049114958#!/compare/1534896000/1534982400

Sold for 15 keys + negligible sweets

Sale 4:

https://backpack.tf/profiles/76561198049114958#!/compare/1534982400/1535068800

https://backpack.tf/profiles/76561198096697494#!/compare/1534896000/1534982400

Sold for Smoking Tree + neglgible sweets

Use there.

Sale 5:

https://backpack.tf/profiles/76561198096697494#!/compare/1535068800/1535155200

https://backpack.tf/profiles/76561198807590356#!/compare/1535068800/1535155200

Sold with Cool SMG for Searing Bone Dome

Bulky?

Sale 6:

https://backpack.tf/profiles/76561198807590356#!/compare/1535155200/1535328000

https://backpack.tf/profiles/76561198084085160#!/compare/1534809600/1535155200

Sold with 3 keys + negligible sweets for Phosphorous Fr-0(17)

Total is 14 keys

Sale 7:

https://backpack.tf/profiles/76561198084085160#!/compare/1535414400/1535500800

https://backpack.tf/profiles/76561198329719416#!/compare/1535241600/1535500800

Untrace.

Sale 8:

https://backpack.tf/profiles/76561198329719416#!/compare/1535500800/1535587200

https://backpack.tf/profiles/76561198410501746#!/compare/1535328000/1535500800

Sold for 17 keys

Sale 9:

https://backpack.tf/profiles/76561198410501746#!/compare/1535328000/1535500800

https://backpack.tf/profiles/76561198145721198#!/compare/1535241600/1535500800

Sold for 18 keys

Sale 10:

https://backpack.tf/profiles/76561198145721198#!/compare/1535587200/1535760000

https://backpack.tf/profiles/76561198095046740#!/compare/1535673600/1535760000

Bulk.

Sale 11:

https://backpack.tf/profiles/76561198095046740#!/compare/1535673600/1535760000

https://backpack.tf/profiles/76561198269408400#!/compare/1535760000/1535846400

Sold for 15 keys

Sale 12:

https://backpack.tf/profiles/76561198135388328#!/compare/1537315200/1537401600

https://backpack.tf/profiles/76561198283091524#!/compare/1528070400/1537401600

Untrace.

Sale 13:

https://backpack.tf/profiles/76561198283091524#!/compare/1537833600/1537920000

https://backpack.tf/profiles/76561198180484678#!/compare/1537833600/1537920000

Keys, not fully traceable.

Sale 14:

https://backpack.tf/profiles/76561198180484678#!/compare/1537920000/1538006400

https://backpack.tf/profiles/76561198126947267#!/compare/1537920000/1538006400

Sold for Pro KS Flamethrower Kit(19)

Sale 15:

https://backpack.tf/profiles/76561198126947267#!/compare/1537920000/1538006400

https://backpack.tf/profiles/76561198266876790#!/compare/1537833600/1538006400

Sold for 15 keys

Total sales @:

14, 15, 15, 15, 17, 18, 18, 19 keys

https://i.imgur.com/lbS6j4Y.jpg

Buyers up to 15 keys

Considering all 15 sales happened incredibly fast,

Taking 17 - 19 keys