Sale 1 :

Before : http://backpack.tf/profiles/76561198060212574?time=1439967600

After : http://backpack.tf/profiles/76561198060212574?time=1440054000

Sold for a Steaming Polar Pullover ( 95 ) but a Sunbeams Dread Knot ( 25 ) was added : 95 - 25 = 63 keys

Mini on the pullover :

Before : http://backpack.tf/profiles/76561198067056647?time=1439449200

After : http://backpack.tf/profiles/76561198067056647?time=1439622000

Sold for Circling Peace Sign Brown Bomber ( 115 ) + 7 keys in items and pure : 122 * 0.9 = 110 keys

Capped at 95 keys : http://www.tf2outpost.com/trade/26709507

Sale 2 :

Before : http://backpack.tf/profiles/76561198068651268?time=1439103600

After : http://backpack.tf/profiles/76561198068651268?time=1439190000

Sold for a Circling TF Logo Coldsnap Cap ( 111 ) not outdated by much, only 1 in the world and no recent sales so taking its current price of 111 keys but 47 keys were added ( http://backpack.tf/profiles/76561198068654774?time=1439103600 ) : 111 - 47 = 64 keys Not applying overpay as adds were on the viewfinders side so it was probably offered.

Sale 3 : Sold for 75 keys in buds

http://www.tf2outpost.com/trade/27013247

Sale 4 : Sold for 70 keys

http://www.tf2outpost.com/trade/27143975

Only recent usable sales.

Taking the range of 65-75 keys.

Supportive criticism welcome

PS : a big thanks to marty for the help and the one for some sales :)