3 in existence, they are all on outpost right now

http://www.tf2outpost.com/trade/13460175 - B/O 5 buds

Cannot for the life of me find what this sold for, history moves way too fast

http://www.tf2outpost.com/trade/13064372 - B/O 3 buds

Looks to have sold for 2 buds + 8 keys + 3.3 keys sweets= ~2.5 buds

BP after trade: http://backpack.tf/id/76561198063112844?time=1375340400

Bud histories don't match up somehow, but here are the buds in the buyers BP the day before the sale to prove he paid them as well as the keys in between the buds: http://backpack.tf/id/76561198066271242?time=1375167600

http://www.tf2outpost.com/trade/13552604 - "quickelling" for 3 buds for 3 days, 45 views

http://www.tf2outpost.com/trade/13110090 - priced 3 buds

Sold for 2 buds + white bills = ~2.4 buds

Checked both BP histories for this one to verify

Buyer: http://backpack.tf/id/76561198025329724?time=1376118000 -> http://backpack.tf/id/76561198025329724?time=1376204400

Seller: http://backpack.tf/id/76561198048570464?time=1376118000 -> http://backpack.tf/id/76561198022112537?time=1376204400

http://www.tf2outpost.com/trade/13555763 - B/O 4 buds

no notable offers

http://www.tf2outpost.com/trade/13541046

best offer so far Vivid Tam o shanter(~1.4) + Die Job Filimental(probably 4-5 keys) = ~1.6 buds

http://www.tf2outpost.com/trade/12697143

Sold for Knifestorm VV Merry(~5.1 very very outdated, also very outlier-ish)

http://www.tf2outpost.com/trade/12650547

Sold for Dead Presidents Handle(not priced) + Nuts Festivizer(~16 keys)

Price Talk - Suggested Range: 2.4 - 2.5 buds

With 2 sales at 2.4-2.5, this is an easy one. There was a sale for a knifestorm merry, but this is obviously a gross overpay given that it is double the value of the next highest sale and no other sales or offers even come close to it.

On second looking at this, that second sale is hard to verify. However, between the 10th and the 11th (when he bought the hat), the buyers backpack value goes down by about ~103 USD (from buying an unpriced hat), which is ~2.36 buds. As for the seller, his backpack value increased by over 800 dollars, which means he did multiple transactions within that day (which I suspected while researching that sale).

This isn't exactly proof by itself, but it alleviates some of the concerns I had that the hat actually had sold for much more than I had suggested(in reality, it suggests that my suggested sale was very close or right on the mark).