Hopefully i'm learning.

Sale 1: (SCM), Probably QS.

https://backpack.tf/profiles/76561198054825186#!/compare/1554940800/1555027200

https://backpack.tf/profiles/76561198080179568#!/compare/1554940800/1555027200

Sale 2: Use There.

Sold For Circling Peace Sign Mann-O-War.

https://backpack.tf/profiles/76561198195420449#!/compare/1556323200/1556496000

https://backpack.tf/profiles/76561198018471515#!/compare/1525046400/1556323200

Sale 3: ~16 Keys Pure.

https://backpack.tf/profiles/76561198080179568#!/compare/1553904000/1553990400

https://backpack.tf/profiles/76561198208594273#!/compare/1553299200/1555891200

Markeplace.tf Sales:

https://marketplace.tf/items/30114;5;u61

Sale 4: ~17 Keys.

Apr 19

$29.99 / $1.78 = 16.85 keys

Sale 5: ~18 Keys.

May 18

$31.99 / $1.82 = 17.58 keys

Including Sale: 16

Going With 16 Flat, one month old seller at 16 and 2 months old seller at 16.43 - https://gyazo.com/a7dcf3df7765df40fa208a31e189f5b6

Thanks to scourge for the premium!