Sale #1

http://www.tf2outpost.com/trade/26352445

Sold for a Searing Samur-Eye (30)

http://backpack.tf/profiles/76561198026466007?time=1435302000 (June 26th)

http://backpack.tf/profiles/76561198026466007?time=1436166000 (July 6th)

Samur-Eye: http://www.tf2outpost.com/trade/26375989 (B/O was 30)

Using 30 keys since it seems the Cowl was likely offered.

Sale #2

http://www.tf2outpost.com/trade/26341884

Sold with 1 key + minor items for a Specialized Australium Wrench (~25)

http://backpack.tf/profiles/76561198037238070?time=1435734000 (July 1st)

http://backpack.tf/profiles/76561198037238070?time=1435820400 (July 2nd)

Wrench: http://www.tf2outpost.com/trade/26327087 (likely offered on)

25 - 1 = 24 keys

Sale #3

http://www.tf2outpost.com/trade/26021475

Sold for 1 bud (3) + G. Point & Shoot (2) + 2 Festive Rocket Launchers (~3) + ~18 keys

http://backpack.tf/profiles/76561198131235654?time=1432882800 (May 29th)

http://backpack.tf/profiles/76561198131235654?time=1432969200 (May 30th)

((3 + 3 + 2) * 0.9) + 18 = 25 keys

Sale #4

http://www.tf2outpost.com/trade/26049554

Sold with 1 key for a Max (25.5)

http://backpack.tf/profiles/76561198054743055?time=1432796400 (May 28th)

http://backpack.tf/profiles/76561198054743055?time=1432882800 (May 29th)

1 - 25.5 = 24.5; rounded to 24 keys