First one in a while, hope I'm not rusty.

There are 4 of these in existance, one is on outpost, this suggestion covers all the sales of that one hat.

http://www.tf2outpost.com/trade/13678437

-offered Burning Festivizer(~2.8) + Vivid HWAH(~1.6) + sweets = ~4.4 + ?

Looks to have sold 1:1 for Cauldron Tossle(~4.7 outdated, but had a very close offer, so ~4.7 is probably fine)

Bp History jumps too fast, had to go by outpost

http://www.tf2outpost.com/trade/13671593

Quicksold for HH(gifted by creator) + 12 keys = ~3 buds

BP after trade: http://backpack.tf/id/76561198078720981?time=1376550000

Previous owner was banned on outpost, but looks like he bought it for a Cloud 9 HWNN(no price) and the other guy added 2.5 buds.

http://www.tf2outpost.com/trade/13124138

Quicksold for 3 buds

BP after trade: http://backpack.tf/id/76561198066377077?time=1374994800

http://www.tf2outpost.com/trade/13011558

http://www.tf2outpost.com/trade/12909437

Memory Leak Brainiac sold for the Phosphorus Waxy. Waxy = ~5.8, the high range on that brainiac is ridiculous, and probably outdated, also considering refined boost, I took the low end to be conservative.

Same owner looks to have sold it for a Bubbles Tossle(~1.8) - outlier

http://www.tf2outpost.com/trade/14012937 current owner - B/O 6 buds

-best offer smoking TC(~4.5) if he adds, rejected