One ([url]http://www.tf2outpost.com/trade/11509537[/url]) was recently sold in a private deal with multiple unusual hats involved. I don't know the exact details but know this from the comment by this seller on another trade ([url]http://www.tf2outpost.com/trade/11429115[/url]). This one did indeed sell very quickly so the best that I can say from this evidence is that he wanted to sell it quickly and safely. I am therefore taking the 28 keys to be the low end, which is about 1.1-1.2 buds. To account for the current fluctuation in monetary value, I'll safely start this suggestion at 1.2 buds here.

As for the higher end, I'm looking at another that recently sold. [url]http://www.tf2outpost.com/trade/11519139[/url] Obviously this is a bit of a mess and probably involved significant over-pay with items. To get a value from this, I'm observing the buyer's backpack history. [url]http://backpack.tf/profiles/76561198082481773[/url] The sudden drop by $70 can be considered, using the current bud value of $45.70, as about 1.5-1.6 buds. Due to it being a non-pure payment and to avoid having an unnecessarily large range, I'll call that a 1.5-bud swap.

EDIT: I just realised that there are currently three suggestions for this hat. Please let me know if you believe that I have missed anything important.