This thing looks so cute.

Sale 1

http://www.tf2outpost.com/trade/22227027 - Sold for 3.7 buds

Sale 2

http://www.tf2outpost.com/trade/20230884 - Sold for a Cauldron Bubbles Prince Tavish's Crown (2.2 buds) and Disco Beat Down Western Wear (1.8 buds) + 8 keys (4*0.9 + 0.4 = 4 buds) (1 bud = 20 keys)

Mini for Cauldron Bubbles Prince Tavish's Crown

http://backpack.tf/vote/id/54141c36ba8d88c5658b49a2

Sale 3

http://www.tf2outpost.com/trade/22059283 - Sold for a Cloud 9 Dr's Dapper Topper + 1 key (2.7*0.9 + 0.1 = 2.5 buds) (Outlier)

Sale 4

http://www.tf2outpost.com/trade/21972050 - Sold for 5.7 buds in items (5.7*0.9 = 5.1 buds) (Outlier)

Sale 5

http://www.tf2outpost.com/trade/21682144 - Sold for an Aces High War Pig (3*0.9 = 2.7 buds) (Outlier)

Sale 6

http://www.tf2outpost.com/trade/21638856 - Sold for a Green Energy Bootleg Base Metal Billycock (Clearly outlier)

Sale 7

http://www.tf2outpost.com/trade/21545940 - Sold for a Strange Professional Killstreak Australium Rocket Launcher (3.5*0.9 = 3.2 buds)

Mini for Strange Professional Killstreak Australium Rocket Launcher

http://www.tf2outpost.com/trade/21638924 - Sold for 3.5 buds

Sale 8

http://www.tf2outpost.com/trade/21494121 - QS for 3 buds

Sale 9

http://www.tf2outpost.com/trade/21487395 - Sold for a Demonflame Ye Oiled Baker Boy (3.7*0.9 = 3.3 buds)

Conclusion: As 3-bud are QS (sale 9) so it's safe to say sale 3, 6, 7 are outlier. Sale 4 is just too high and kinda dubious as I don't know what got involved. New value: 3.2 - 4 buds.

Feel free to counter / support my proofs.