Sale 1:

Sold for Disco Beat Down Galvanized Gibus (59.5)

No outpost

Seller: https://backpack.tf/profiles/76561198055617854#!/compare/1505347200/1505433600

Buyer: https://backpack.tf/profiles/76561198272076942#!/compare/1505347200/1505433600

X = 60

Sale 2:

Sold for Cool Minimal Wear Sniper Rifle of some sort (Mini at 40 below) + 13 keys

No outpost

Seller: https://backpack.tf/profiles/76561198118148699#!/compare/1510099200/1510185600

Buyer: https://backpack.tf/profiles/76561198136105456#!/compare/1510099200/1510185600

X = 53

Sale 3:

Sold with ~1 key in items 45 keys in ~3 days

No outpost

Seller: https://backpack.tf/profiles/76561198136105456#!/compare/1510444800/1510531200

Buyer: https://backpack.tf/profiles/76561198264853358#!/compare/1510358400/1510444800

X = 44

Sale 4:

Sold for Green Confetti Killer Exclusive

No outpost

Seller: https://backpack.tf/profiles/76561198268005140#!/compare/1504915200/1505001600

Buyer: https://backpack.tf/profiles/76561198141219789#!/compare/1504915200/1505001600

Probably better to use on the KE.

Sniper Rifle Mini:

Sold for 40 keys

No outpost

Seller: https://backpack.tf/profiles/76561198069740698#!/compare/1509926400/1510099200

Buyer: https://backpack.tf/profiles/76561198118148699#!/compare/1510099200/1510185600

X = 40

Sellers:

56 keys:

https://i.imgur.com/V54si1L.png - very young

65 keys:

https://i.imgur.com/LpxGsCC.png - 2 months

85 keys:

https://i.imgur.com/7nx4hTY.png - 6 months

Sales at:

44

53

60

44 sold kinda quickly, excluding 44.

Going with 53-60.