Figured I'd try and update this ancient price for future owners. I'm basing my value off four different trades:

http://www.tf2outpost.com/trade/16492596 - A two-month-old trade in which a guy purchases the Jeepcap off Koga for what appears to have been a Scorching Flames brain Bucket + 15 keys (~4 buds, maybe more, after overpay).

http://www.tf2outpost.com/trade/16606826 - A month+-old trade in which the above buyer had a few 3-3.7-ish unusual offers, depending on how you value the other hats mentioned. Notable offers include a C9 Milkman (valued at 3.5) and a Terror-Watt Cannonball if the Jeepcap owner added his Terror-Watt Tin-Gallon (The Cannonball, while unvalued, is probably 6-ish buds like the Kill-a-Watt version; the Tin-Gallon being valued at 2, after overpay this offer is likely worth ...~3.4-3.7?). He never accepted an offer, and has the hat at the time I posted this.

http://www.tf2outpost.com/trade/17795146 - The trade in which I purchased the hat; I obtained it, plus 6-7 keys worth of sweets, for my Smissmas Caribou (~3.5 after factoring sweets). The Caribou was indeed valued at the time (though it was just posted that day).

http://www.tf2outpost.com/trade/17997183 - The trade in which I sold the hat. I sold for a P. Fetti Stash (2.7 after overpay) plus a bud, for 3.7 total.

I can't find any proof of the hat selling for below 3 - in fact, the last vote didn't either, meaning it should definitely be outside the range. While my proof gives little support for the low-end, it seems better to be conservative rather than raising the low-end any more than I'm already suggesting.

I know the proof I'm offering is a bit tight - I'm gleaning a proof of sale from 2 months ago, and only using two proofs I'm not directly involved in - but, like all limited-release hats, there's not much movement to work with.