Hey guys, this is my first unusual suggestion!

Again thanks to Brendan ( http://backpack.tf/u/76561198031371895 ) and Doc Scratch ( http://backpack.tf/u/76561198036907469 )

Also this hat is 1 of 1, so I was able to find every single valid sale there has ever been.

Sale 1:

Sold for a Kill a Watt Head Splitter

http://www.tf2outpost.com/trade/25003533

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

Backpack Histories:

The seller before http://backpack.tf/profiles/76561198036907469?time=1423641600

The buyer after http://backpack.tf/profiles/76561198055363275

4.3 x 0.9 = 3.87 (rounding to 3.9 buds)

Sale 2:

Sold with 3 keys for a Searing Plasma Anger

http://www.tf2outpost.com/trade/25002908

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

(4.2 x 0.9) - 0.24 (3 keys) = 3.54 (rounding to 3.5 buds)

Sale 3: (support proof)

Sold for 3.5 buds worth of cash via Paypal

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

Proof that it wasn't bought for TF2 items

Before http://backpack.tf/profiles/76561198042863866?time=1421913600

After http://backpack.tf/profiles/76561198042863866?time=1423382400

Notes:

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

Conclusion:

Sales at 3.5, 3.9 and a support-sale of 3.5 buds. Taking a final range of 3.5-3.9 buds.

Feel free to support/counter my suggestion!