Sale 1 :

Before : http://backpack.tf/profiles/76561198039260350?time=1439103600

After : http://backpack.tf/profiles/76561198039260350?time=1439362800

Sold for a Sunbeams Professional's Panama : 48 keys

Mini on the panama :

Before : http://backpack.tf/profiles/76561198043614216?time=1436338800

After : http://backpack.tf/profiles/76561198043614216?time=1436425200

Sold for a Circling Heart Pugilist's Protector ( 25 ) + a Purple Confetti Ye Olde Baker Boy ( 28 ) : 53 * 0.9 = 48 keys

Sale 2 : http://www.tf2outpost.com/trade/26629725 Outlier

Before : http://backpack.tf/profiles/76561198001771869?time=1438239600

After : http://backpack.tf/profiles/76561198001771869?time=1439362800

Sold for a Burning Flames Professional's Panama ( 53 ) + spec ks aussie sniper ( 48 ) : 53 * 0.9 + 48 = 96 keys

Sale 3 :

Before : http://backpack.tf/profiles/76561198087125768?time=1437980400

After : http://backpack.tf/profiles/76561198087125768?time=1438153200

Sold as well as a Stormy 13th Hour Brigade Helm ( 100 ) + 15 keys + 7 keys in items for a Purple Energy Modest Pile of Hat ( 164 ) : 164 - 122 = 42 keys

Calling sale 2 an outlier because of how far apart it is from the other 2 sales.

Thus taking the range of 42-48 keys

Supportive criticism welcome