Proof below.

Sales:

http://www.tf2outpost.com/trade/15048694

-sold for 1.5 buds

http://www.tf2outpost.com/trade/15435183

-paradox sold/bought his peace noble for 1 bud (check history)+professor: http://www.tf2outpost.com/trade/15435183

-noble (check history): http://www.tf2outpost.com/trade/15444147

-1.7 buds

http://www.tf2outpost.com/trade/14362132

-sold for 2 buds+5 keys=~2.3 buds

-seller's bp:

http://backpack.tf/id/76561198028202774?time=1381474800

http://backpack.tf/id/76561198028202774?time=1381561200

http://www.tf2outpost.com/trade/14142905

-sold for smoking brigade=1.2 buds, outlier, likely because he seems to have no experience, being the unboxer

Current trade:

http://www.tf2outpost.com/trade/15691227

-wants 4.4 buds

Sales: 1.2, 1.5, 1.7, 2.3

1.2 is too low, 1.5 still seems alright and took a while to sell. So 1.5-2.3. Unusual overpay and original prices used.