Probably my longest suggestion yet :P Burning Cock ;^)

Sale 1:

Sold for a Circling Heart Tyrant's Helm

(106*0.9) = 95.4 rounding to 95 keys

http://www.tf2outpost.com/trade/25963119

http://backpack.tf/profiles/76561198056544276?time=1433055600 (May 31st)

http://backpack.tf/profiles/76561198056544276?time=1433142000 (June 1st)

Sale 2:

Sold for a Purple Energy Defiant Spartan and a Haunted Ghosts Dr's Dapper Topper

(49 + 40)*0.9 = 80.1 rounding / capping to 80 keys

http://www.tf2outpost.com/trade/26011213 B/O of 80

http://backpack.tf/profiles/76561198069441398?time=1432796400 (May 28th)

http://backpack.tf/profiles/76561198069441398?time=1432882800 (May 29th)

Sale 3: (outlier)

Sold with an Australium Scattergun for a Sunbeams Pot, 4 keys and 3 keys of paints

(3*0.9) + 98 + 4 - 34 = 70.7 rounding to 71 keys

http://www.tf2outpost.com/trade/25594327

http://backpack.tf/profiles/76561198121890168?time=1430550000 (May 2nd)

http://backpack.tf/profiles/76561198121890168?time=1431673200 (May 15th)

Sale 4: (outlier, quicksell)

Quicksold for a Burning Beanie and a Stormy Storm Counterfeit Billycock

59 + 13 = 72 keys

http://www.tf2outpost.com/trade/26104254

http://backpack.tf/profiles/76561198043044699?time=1433055600 (May 31st)

http://backpack.tf/profiles/76561198043044699?time=1433228400 (June 2nd)

Notes:

Quicksell at 72 makes 71 an outlier

Mini for the Haunted Ghosts Dr's Dapper Topper: ~40

B/O of 40 for 3 months

http://www.tf2outpost.com/trade/25226018

Mini for the duped Sunbeams Pot: ~98

(slightly outdated sale, however it is the only recent one for a duped Beams pot)

Sold for 4 buds and a GE pot (buds were 14.5)

(44*0.9) = 58 = 97.6 rounding to 98 keys

http://backpack.tf/profiles/76561198037947164?time=1420358400 (January 4th)

http://backpack.tf/profiles/76561198037947164?time=1420531200 (January 6th)

Mini for the Burning Beanie:

Sold for a Purple Energy Backbiter's Billycock, an Australium Ambassador, an Aces High Virtual Reality Headset and 5 keys

(30 + 13.5)*0.9 + 15 + 5 = 59.15 rounding to 59 keys

http://backpack.tf/profiles/76561198079042246?time=1425369600 (March 3rd)

http://backpack.tf/profiles/76561198079042246?time=1425542400 (March 5th)

Mini for the Stormy Billycock:

2 sellers at 13 and 1 at 12

13 keys

http://www.tf2outpost.com/search/248070380

Conclusion:

Quicksell at 72 makes 71 an outlier, taking the final range at 80 to 95 keys.