Hey! Wooo yellow belt :D This hat is 1 of 1, I managed to find the only valid sale. One sale is exactly 3 days too old to use, 1 sale involves 3 other unpriced unusuals in a giant unusual trade, and the last 2 sales are for CSGO items. Anyway, here it is.

Sale 1:

Sold for a Time Warp Firewall Helmet (3.7*0.9 = 3.33) rounding to 3.3 buds

Before: http://backpack.tf/profiles/76561198118493189?time=1424764800

After: http://backpack.tf/profiles/76561198118493189?time=1424851200

Mini for Firewall Helmet:

I went to go do a mini for this, but it looks like someone else has got me covered:

http://backpack.tf/vote/id/54f2cc00b88d88aa588b47f2

I took the average of his range (which comes out to 3.7 buds) as my price in the above sale.

Notes:

http://www.tf2outpost.com/trade/25324208 - B/O of 3.5 buds

Conclusion:

One sale at 3.3 buds, and a B/O of 3.5. You can't base the high end off a B/O, thus taking the final price at 3.3 buds.