Proof below. Overpay calculated. Original prices used

Sales

Credit to Poker for providing the following sale:

http://imgur.com/Sd8nqjK http://imgur.com/KHCZnFl http://www.tf2outpost.com/item/440,2009961638

Blizz Dragonborn + 2 buds = 4.2 buds

http://www.tf2outpost.com/trade/15031051

Aces High Voodoo Juju, other guy added ~10 keys? = 3.8 buds

Side note: Inventory history seems to be all jumbled up D: Hard to confirm this

http://www.tf2outpost.com/trade/14787430 - Time Warp Prancer's = 2,5 buds (outlier)

Conclusion

3 sales, one of which is an outlier. Vote accordingly.

Help / Constructive Criticism / Additional Proof / Counter-Proof is ALWAYS welcome! >;3