Sale 1:

https://backpack.tf/profiles/76561198370800561#!/compare/1548633600/1548806400

https://backpack.tf/profiles/76561198209640976#!/compare/1548720000/1548806400

Sold for spell, bulky

Sale 2:

https://backpack.tf/profiles/76561198209640976#!/compare/1548633600/1548806400

https://backpack.tf/profiles/76561198243211546#!/compare/1548633600/1548806400

Sold for Stormy Slouch + 1 key

Slouch Mini:

https://backpack.tf/suggestion/5c7a4fbbd381725a6e5ade68

Suggestion for 13 keys

Total is 14 keys

Sale 3:

https://backpack.tf/profiles/76561198243211546#!/compare/1548633600/1548806400

https://backpack.tf/profiles/76561198062292065#!/compare/1548720000/1548806400

Sold for Clair Highway Star

Star Mini:

https://backpack.tf/suggestion/5c7b1c7b67807215367c85ea

Suggestion for 16 keys

Sale 4:

https://backpack.tf/profiles/76561198062292065#!/compare/1548806400/1548979200

https://backpack.tf/profiles/76561198094771363#!/compare/1548720000/1548892800

Sold for 8 keys?

Sale 5:

https://backpack.tf/profiles/76561198094771363#!/compare/1548892800/1548979200

https://backpack.tf/profiles/76561198148843171#!/compare/1548892800/1548979200

Sold for 10 keys

Sale 6:

https://backpack.tf/profiles/76561198148843171#!/compare/1549238400/1549324800

https://backpack.tf/profiles/76561198308315479#!/compare/1549065600/1549324800

Sold for OF Toe + ~5 keys in sweets

Toe Mini:

https://backpack.tf/suggestion/5c7a51b3d381725bdb200122

Suggestion for 8.5 keys

Total is 13.5 keys

Sale 7:

https://backpack.tf/profiles/76561198308315479#!/compare/1549065600/1549324800

https://backpack.tf/profiles/76561198334946156#!/compare/1549238400/1549324800

Keys

Sale 8:

https://backpack.tf/profiles/76561198334946156#!/compare/1549324800/1549411200

https://backpack.tf/profiles/76561198003698220#!/compare/1549324800/1549411200

Bulk

Sale 9:

https://backpack.tf/profiles/76561198003698220#!/compare/1549411200/1549497600

https://backpack.tf/profiles/76561198134266699#!/compare/1549411200/1549497600

Broker / bulk

Sale 10:

https://backpack.tf/profiles/76561198134266699#!/compare/1549584000/1549670400

https://backpack.tf/profiles/76561198083000445#!/compare/1549584000/1549670400

Bulk

Sale 11:

https://backpack.tf/profiles/76561198083000445#!/compare/1549670400/1549756800

https://backpack.tf/profiles/76561198148843171#!/compare/1549670400/1549756800

Sold for 8 keys

Sale 12:

https://backpack.tf/profiles/76561198148843171#!/compare/1549670400/1549756800

https://backpack.tf/profiles/76561198003456281#!/compare/1549584000/1549756800

Sold for 12 keys

Sale 13:

https://backpack.tf/profiles/76561198003456281#!/compare/1549584000/1549756800

https://backpack.tf/profiles/76561198094475535#!/compare/1549670400/1549756800

Sold for 14 keys

Total sales @:

8, 8, 10, 12, 13.5, 14, 14, 16 keys

Buyers up to 7.77 keys,

Seller at 25 keys,

Let's take 12 - 16 keys, preserve range around most sales.