so many sales for a 1 of 1 hat...

Sale 1:

Sold for 1 bud + P.Fetti Noble (2.3*0.9) = 1 + 2.07 = 3.07 (rounding to 3.1)

http://www.tf2outpost.com/trade/24495579

Sale 2:

Sold for Time Warp Tin Sola Topi* (2.8*0.9) = 2.52 (rounding to 2.5)

http://www.tf2outpost.com/trade/24137772

http://backpack.tf/profiles/76561198057171057?time=1418566695 → http://backpack.tf/profiles/76561198057171057?time=1418630400

Sale 3:

Sold for 3 buds

http://www.tf2outpost.com/trade/24487163

http://backpack.tf/profiles/76561198025119115?time=1420444800 → http://backpack.tf/profiles/76561198025119115?time=1420531200

Sale 4:

Sold for Demonflame Pyro's Boron Beanie* (2.7*0.9) = 2.43 (rounding to 2.4)

http://www.tf2outpost.com/trade/24609044

http://backpack.tf/profiles/76561198148213574?time=1421049600 → http://backpack.tf/profiles/76561198148213574?time=1421188038

Sale 5: (invalid sale, outlier; sold in less than a day)

Quicksold for 1 buds + 6 keys = 1 + 0.4 = 1.4

http://www.tf2outpost.com/trade/24644829

http://backpack.tf/profiles/76561198120552341?time=1421272307

Sale 6: (invalid sale, outlier; sold in less than a day)

Sold for 22 keys (22/15) = 1.46 (rounding to 1.5)

http://www.tf2outpost.com/trade/24644976

http://backpack.tf/profiles/76561198052367336?time=1421278267

Mini for Demonflame Pyro's Boron Beanie*:

Sold for Planets Bonk Boy (3*0.9) = 2.7

http://www.tf2outpost.com/trade/24382608

http://www.tf2outpost.com/item/440,3400694203,451,5 → http://www.tf2outpost.com/item/440,3400692839,30040,5

Mini for Time Warp Tin Sola Topi*:

Sold with Planets Stovepipe ([13/13]*0.9) + 9 keys (9/13) for Cloud 9 Cannonball (3.3) + 1 buds

X + 0.9 + 0.69 = 3.3 + 1

X = 4.3 - 1.59 = 2.71 (rounding to 2.7)

http://backpack.tf/profiles/76561198049834485?time=1419667200 → http://backpack.tf/profiles/76561198095557579?time=1419711508

http://www.tf2outpost.com/trade/24297144 - B/O of 37 keys (~2.9 buds at the time)

~ Taking a value of 2.8 buds.

Notes:

For valuing the buds, I'm using the price at the time of sale.

Conclusion:

Sales at 2.4, 2.5, 3, 3.1, and quicksales at 1.4, 1.5. Taking final range of 2.4-3.1 buds.

Feel free to support/counter my suggestion!