My suggestion had 84% upvote, but I will not stand to false prices. I will make a range.

Past sales

Going from oldest to youngest.

1st proof

http://www.tf2outpost.com/trade/12700452 - Sold for a Kill-a-watt Waxy Wayfiner (Has no price)

2nd proof

http://www.tf2outpost.com/trade/12820666 - Sold for a NNB Noble (1.4) + Bliz Jeepcap (1.1) + OF Private Eye (1.2) + Sweets (No clue)

Basically 3.7 buds. This one is an outlier.

3rd proof

http://www.tf2outpost.com/trade/13048453 - Traded for Heavy Duty Rag (1.8 - 2.1), owner of mongolian added sweets ->. 1.7 buds.

Heavy Duty Rag = 1.8 - 2.1 buds, so 1.8 buds basically. We will go down a bit to 1.7 to count for the sweets. Don't know what the sweets are.

4th proof

http://www.tf2outpost.com/trade/12873064 - Sold to me. Traded for my Steaming Bonk boy (2.1) and he added 11 keys so... 1.6 buds

My Sale

Sold for a stormy Lucha (1.7 - 1.9) -> 1.7 bdus

http://oi41.tinypic.com/3133oya.jpg

My backpack with Stormy Lucha : http://backpack.tf/id/76561198059230343

His backpack with the Roboactive Mongolian : http://backpack.tf/profiles/76561198073583273

Tell me if I need more proof, and please give me tips on taking screenshots, I am uber shit at it.