This is the hat I unboxed! Setting a first price for it...

I received an offer of a Max's Head + 4 Buds, but was later retracted in less than 24 hours. I hear he re-offered 4 buds pure to the next owner, but was not willing to go higher than that (rejected). Not sure if we'd count that 6 bud offer, but someone was willing to do ~6 pure, at least at the start. Take it with a grain of salt. (My trade: http://www.tf2outpost.com/trade/10874291)

I later sold it for a Stormy KE (5.5-6.1 on bp.tf, multiply by 0.9 gives a range of 5-5.5).

The guy I sold it to (his trade is here http://www.tf2outpost.com/trade/10918971) later sold it for a Burning Shako (4.7-5.2 buds on bp.tf, multiply by 0.9 gives 4.2-4.7). (This is new owner, I added him, and he said he paid a Burning Shako 1:1 for it. Here is the new trade http://www.tf2outpost.com/trade/11055684)

Given the 4 bud + Max Head offer was just hype since it was offered to me three hours after I unboxed it, it seems like this hat was sold at a low of 4.5 (middle of Burning Shako trade) and a high of about 5.5 (taking the high value of the KE in part due to the 4 bud + max head offer).

So, 4.5-5.5 seems like a fair price at the moment.