Proof below.

4 month-old price.

Sales:

http://www.tf2outpost.com/trade/15551186

-sold for aces noble=~4.5 buds

-noble: http://www.tf2outpost.com/item/440,2065052893,137,5

http://www.tf2outpost.com/trade/15365623

-b/o of 5.5 buds

-sold for logo spartan+burning mongolian+black bills+8 keys (his original offer was hidden)

-buyer's bp, no sweets seem to have been added except keys:

http://backpack.tf/id/76561198049518106?time=1383116400

http://backpack.tf/id/76561198049518106?time=1383202800

-bills: http://www.tf2outpost.com/trade/15370932

-some keys: http://www.tf2outpost.com/trade/15380220

-~4.1 buds, this sale is a little unclear but doesn't form the range

http://www.tf2outpost.com/trade/14938935

-wanted 4.5 buds

-sold for $169.99 USD on steam market, which should be in my range

http://www.tf2outpost.com/trade/14355027

-b/o of 5 buds

-sold for 4 buds

-seller's bp:

http://backpack.tf/id/76561197973980392?time=1379746800

http://backpack.tf/id/76561197973980392?time=1379833200

Current trades with offers:

http://www.tf2outpost.com/trade/12024636

-very old trade

-notable recent offers:

disco metal slug (5.1 outlier)

ghosts fez (4.3)

beams jeepcap (4.1)

aces tower (4.4)

level 1 max+headcase+9 keys (4.7)

cauldron pot+sulph hwah (4.9)

http://www.tf2outpost.com/trade/15713193

-notable offers:

peace+ghosts spartans (4.5)

phos panama (outdated)+32 keys (4.1)

SF RL+2 buds (4)

4 is from a sale and an offer, would be a good low end. 4.9 is from the offer of cauldron pot+sulph hwah since the offers show it can go higher than the sales. Unusual overpay and original price used.