5 month old price!

Sale 1:

Sold for Ghosts Kabuto (5*0.9) + 2 buds (2) + Black Paint (~0.11) = 4.5 + 2 + 0.11 = 6.61 (rounding to 6.6)

http://www.tf2outpost.com/trade/22849205

http://i.imgur.com/q4saxkD.png

Sale 2:

Sold with 1 buds (1) + BMOC (~0.65) for a *Duped Burning Le Party Phantom (8.05*0.9) = 7.245 - (1+0.65) = 5.595 (rounding to 5.6)

http://www.tf2outpost.com/trade/22395832

http://backpack.tf/profiles/76561198103929624?time=1409554800 → http://backpack.tf/profiles/76561198103929624?time=1410073200

Sale 3: (invalid sale, outdated values on some hats)

Sold for Searing Fro (2.7*0.9) + Vivid Gatsby (2.1*0.9) + Stormy Conquistador (1.2*0.9) + 1 buds (1) = 2.43 + 1.89 + 1.08 + 1 = 6.4

http://backpack.tf/profiles/76561197995194055?time=1408863600 → http://backpack.tf/profiles/76561197995194055?time=1408950000

Sale 4:

Sold for Vivid Kabuto (4.1*0.9) + 2 buds (2) + 4 keys (~0.24) + Sweets (~0.26) = 3.69 + 2 + 0.24 + 0.26 = 6.19 (rounding to 6.2)

http://www.tf2outpost.com/trade/22544123

http://backpack.tf/profiles/76561198073382085?time=1410246000 → http://backpack.tf/profiles/76561198073382085?time=1410418800

Sale 5: (outlier)

Sold for 85 keys (85/17) = 5

http://www.tf2outpost.com/trade/22847422

http://i.imgur.com/1JdSfdg.jpg

Sale 6:

Sold for Poisoned Shadows Pot (5.65*0.9) + 1 buds (1) = 5.085 + 1 = 6.085 (rounding to 6.1)

http://www.tf2outpost.com/trade/22881252

http://backpack.tf/profiles/76561198019190046?time=1412608313 → http://backpack.tf/profiles/76561198062894809?time=1412665200

Sale 7:

Sold for Clean Max's Head (3.3) + 3 buds = 3.3 + 3 = 6.3

http://www.tf2outpost.com/trade/20905580

Sale 8:

Sold for 5 buds (5) + Genuine Horace ([13.5/17]*0.9) = 5 + 0.71 = 5.71 (rounding to 5.7)

http://www.tf2outpost.com/trade/22940997

http://backpack.tf/profiles/76561198047306570?time=1412492400 + http://www.tf2outpost.com/item/440,3037503421,30469,1

Sale 9:

Sold for DBD Dread Riding Hood (7.9*0.9) + Sweets (~1) = 7.11 + 1 = 8.11 (rounding to 6.5 due to B/O)

http://www.tf2outpost.com/trade/22754112

http://www.tf2outpost.com/item/440,3029021601,152,5 → http://www.tf2outpost.com/item/440,2983983429,1095,5

Mini for *Duped Burning Le Party Phantom: (credits to dr1ftec for the proof!)

http://forums.backpack.tf/index.php?/topic/6817-bpbs-mini-suggestion-thread-for-gifted-duped-hats/page-3?p=199017#entry199017

http://www.tf2outpost.com/trade/21362593 - sold for 8 buds ( http://backpack.tf/profiles/76561198062713417?time=1405839600 )

http://www.tf2outpost.com/trade/22370460 - sold for Vivid Phantom (4.9) + Beams L'Inspecteur (3.2) = ~8.1 ( http://www.tf2outpost.com/trade/22374111 )

One sale at 8 and another at 8.1, taking 8.05 as the price.

Notes:

Most, if not all sales occurred when Earbuds were 17 keys flat.

http://www.tf2outpost.com/trade/22994339 - 5.3 buds (5 days, but duped)

Conclusion:

Sales at 6.6, 5.6, 6.4, 6.2, 5, 6.1, 6.3, 5.7, 6.5 and a seller at 5.3. Average = 5.6-6.6, taking range as 5.5-6.5.

Feel free to support/counter my suggestion!