Proof below.

7 month-old price.

Sales:

http://www.tf2outpost.com/user/76561198021274201

-this user bought his cosa for smoking cosa+2 buds=~2.9 buds

-smoking cosa: http://www.tf2outpost.com/trade/13313780

-2 buds: http://www.tf2outpost.com/trade/13687797

-seen here:

http://backpack.tf/id/76561198021274201?time=1375167600 before

http://backpack.tf/id/76561198021274201?time=1375426800 after

http://www.tf2outpost.com/trade/13451732

-bought aces high cosa=4.4 buds lel

-proof: http://backpack.tf/vote/id/521a3475ba253640318b456d , bp history also suggests this

-outlier

http://www.tf2outpost.com/trade/15171020

-b/o of 4 buds

-cosa+7 keys, seems to have bought hearts hwah: http://www.tf2outpost.com/trade/15124788

-seller's bp:

http://backpack.tf/id/76561198077598622?time=1382166000 hearts hwah+135 keys

http://backpack.tf/id/76561198077598622?time=1382252400 cosa+142 keys

-~2 buds, outlier

http://www.tf2outpost.com/trade/15598955

-b/o of 4 buds

-seems to have sold for just the logo beak

-seller's bp:

http://backpack.tf/id/76561198062716217?time=1384156800

http://backpack.tf/id/76561198062716217?time=1384243200

-rejected offer of 30 keys+sf frontier (~2.1)

-~2.6 buds

http://www.tf2outpost.com/trade/15172827

-b/o of 4 buds

-sold in a multiple hat deal it seems, won't use this

-offer of miami gonzilla=~3.2 buds, close enough to price, could be outlier

Current trade:

http://www.tf2outpost.com/trade/15697377

-rejected 2 buds

Sales: 2, 2.6, 2.9, 4.4

Low end and high end pretty clear, org from sales. Unusual overpay and original prices used.