Hopefully this is the last one.

Sold for a Factory New Sand Cannon(22 Keys with Overpay)

http://backpack.tf/profiles/76561197970885814?time=1437116400

http://backpack.tf/profiles/76561197970885814?time=1437202800

Sold for 20 Keys*

http://backpack.tf/profiles/76561198060146051?time=1436511600

http://backpack.tf/profiles/76561198060146051?time=1436684400

*The keys were used to buy a PE Samur-Eye from Rain Man as shown in the histories:

http://backpack.tf/profiles/76561198145255903?time=1436425200

http://backpack.tf/profiles/76561198145255903?time=1436684400

http://backpack.tf/profiles/76561198111977118?time=1436598000

http://backpack.tf/profiles/76561198111977118?time=1436684400

Factory New Sand Cannon mini suggestion

All sales on the SCM at the time(Keys = $2.49): http://steamcommunity.com/market/listings/440/Sand%20Cannon%20Rocket%20Launcher%20%28Factory%20New%29

$65.01

$65.14

$54.86

The average comes out at $61.67(Roughly 24.5 Keys)

Sold for a Max's Severed Head(28 Keys)(Credits to 3v1lcl0n3 for the sale!)

http://backpack.tf/profiles/76561198057908152?time=1439362800

http://backpack.tf/profiles/76561198057908152?time=1440226800

http://www.tf2outpost.com/trade/26634783

http://prntscr.com/8lvm9q

Sales seem to fit, 20-28 Keys should be fine.

Additional Proof/Counter-Proof/Constructive Criticism/Feedback is always appreciated.