Sale 1:

Sold for Fountain of Delight Flippin' Awesome (4*0.9) = 3.6

http://www.tf2outpost.com/trade/21763872

http://backpack.tf/profiles/76561198069393071?time=1407308400 → http://backpack.tf/profiles/76561198109727871?time=1407330528

Sale 2:

Sold for 80 keys (4.21) = 4.21 (rounding to 4.2)

http://www.tf2outpost.com/trade/21833620

http://i.imgur.com/SPhIswB.png

Sale 3:

Sold for Cloud 9 Anger (3.4*0.9) = 3.06 (rounding to 3.1)

http://www.tf2outpost.com/trade/21921013 → http://www.tf2outpost.com/trade/21935374

http://i.imgur.com/5ac2cPP.png

Sale 4: (invalid sale)

Unsure what it sold for

http://www.tf2outpost.com/trade/20939272

Sale 5: (invalid sale)

Unsure what it sold for, more likely sold it on the SCM as backpack history show nothing was traded for them...

http://backpack.tf/profiles/76561198070653812?time=1407797516 → http://backpack.tf/profiles/76561198109727871?time=1407826800

Feel free to support/counter my suggestion!