Well, I forgot about how broken this site has been at storing unusual prices since the fire nation attacked buds dropped, so let's try this again!

http://www.tf2outpost.com/trade/15644483 Sold for a Purple Energy Cowl + 2.5 keys of sweets. See http://backpack.tf/id/76561198050452658?time=1384156800 then http://backpack.tf/id/76561198050452658?time=1384329600. Overpay applied, that's about 5.5 buds. Coincidentally, the owner happened to link to the trade he purchased it from in that same trade.

http://www.tf2outpost.com/trade/14807196 There are offers of up to 11 buds, but they were all retracted over time. The buyer from the previous trade says he bought it for 10 buds. However, this would be a 5 bud outlier, and I can't find any backpack history that shows a ten-bud transaction. All the other high offers were declined or retracted as well, the only other offer standing was an unpriced Terror-Watt Hazmatten and a Flies Cosa. From all this, I'm going to consider this an outlier/unconfirmed trade and ignore it.

http://www.tf2outpost.com/trade/14720521 Sold for Blizzard Tyrant's + 40 keys + a Bill's. One month ago, the Tyrant was ~2.2 buds, 40 keys would equal ~2.3 buds, and the bills would be ~.3. So all in all, ~4.8 buds.