4 of these in existance, there's 2 on outpost right now.

http://www.tf2outpost.com/trade/12868919 - looking for around 4

Sold for Scorching Capos(~4.6)

http://www.tf2outpost.com/trade/12808885 - looking for around 3

Sold for Nuts Cosa + sweets(big outlier)

http://www.tf2outpost.com/trade/12775712

Miami Birdcage(~3) sold for Killawatt Softcap, equal value since softcap was offered first

http://www.tf2outpost.com/trade/12689535 - was selling for 3 buds

http://www.tf2outpost.com/trade/12702473 - B/O 4 buds

http://www.tf2outpost.com/trade/12597993

Sold for Aces High Tower(~4.2)

Price Talk - Suggested Range: 3 - 4 buds

With 2 sold around 3 this is the obvious low end. There were a couple sales above 4, but with multiple people asking for 4 buds thereabouts, it would be too much to go above 4 on the high end.