Okay this took pretty long to do.

(Credits to DamageMan for the two sales below)

Sold for 75 Keys

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

Added 40 Keys for a Spellbound Sergeant's Drill Hat(91 Keys with Overpay)(51 Keys total)

http://i.imgur.com/tdFn8XF.png

Sold for a Morning Glory One-Man Army(34 Keys with Overpay) and 1 Bud(8 Keys at the time)(42 Keys total)

http://backpack.tf/profiles/76561198120366659?time=1427679754 -> http://backpack.tf/profiles/76561198120366659?time=1427785200

Added 1 Key for a Haunted Ghosts Noble Amassment of Hats(43 Keys with Overpay)(44 Keys total)

http://backpack.tf/profiles/76561198067056647?time=1427612400 -> http://backpack.tf/profiles/76561198067056647?time=1427958000

Added 5 Keys for a Terror-Watt Pyromancer's Mask(60 Keys with Overpay)

http://backpack.tf/profiles/76561198067056647?time=1429925734 -> http://backpack.tf/profiles/76561198067056647?time=1429945200

Sold for a Death at Dusk Noble Amassment of Hats(73 Keys with Overpay) and a Festive Scattergun(74 Keys total)

http://backpack.tf/profiles/76561198069516654?time=1428191549 -> http://backpack.tf/profiles/76561198069516654?time=1428217200

Haunted Ghosts Noble Amassment of Hats mini suggestion

(Credits to aaroncsn)

Sold for a Steaming Hong Kong Cone(52 Keys, Offered) and ~3 Keys in Sweets(~55 Keys total)

http://backpack.tf/profiles/76561198069950258?time=1428649200 (April 10th)

http://backpack.tf/profiles/76561198069950258?time=1428735600 (April 11th)

http://www.tf2outpost.com/trade/25632898

Noble B/O was 40 Keys whe the sale was done: http://www.tf2outpost.com/trade/25422060

Using 40-55.

Both sides have equal support, so a high range might be necessary. 42-75 Keys should be fine.

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