I was interested in this hat and the first one( the owner) of the hat i offered him vivid plasma brigade + small sweet's for 5 or 6 keys, he declined and another guy offered him a 3 buds pure and he sold it for him. i think it's high price for this hat since i bought once burning for 2 buds pure. sorry Downvote

Only offer is a troll one. If there was an offer in the 3.7-4 range, it's been retracted.

http://www.tf2outpost.com/trade/6238422 - Though the previous owner was asking for 3.5 buds, and while we don't know the actual trade it looks like the current owner was interested at that price.

For the first trade, it looks like it may have went for a festive scattergun + festive bat. Though this is based off the next trade after the pugilist being closed is those two items, both having previously been owned by the next owner. So that'd also be ~3.5 buds, based on prices at the time.

I'd be happier if the price included 3.5 buds in the range, since it seems to have traded twice consistently at that price. Though both involve a good degree of assumption, so there may not be enough information altogether here.