My partner purchased one of these as a gift for me.

TF2 Outpost trade where is was purchased: http://www.tf2outpost.com/trade/23406242

He offered 2.5 earbuds, however that was declined.

So he paid 2 earbuds and 12 keys, which according to to-days values is 2.8 earbuds.

Proof of purchase: http://i.gyazo.com/10f87a9d2860dc0b4334481badebe26c.png

Other proofs of trades.

http://www.tf2outpost.com/trade/23380767

Sold to: http://steamcommunity.com/id/Miss_Yamaxanadu/

For: Searing plasma Samur-Eye, Strange Bushi-Dou, and Strange Sangu Sleeves.

Mini-suggestion:

Searing plasma Samur-Eye was Sold for 54 keys at the time was 3.3 buds with buds being 16.25 keys

Proof

http://www.tf2outpost.com/trade/22902115

Before overpay calculations with sweets: 3.7 earbuds

Factoring in overpay and sweets that brings it 3.3 earbuds on the second sale of a Searing Plasma Das Gutenkutteharen.