One of one hat, but circulates quite a bit. Let's first start with what I sold it for, and then move on to others.

[url]http://bazaar.tf/trade/244671[/url]: Sold it for ~35 keys in items and keys. So ~1.4 buds.

[url]http://www.tf2outpost.com/trade/11531828[/url]: Had a C/O of pure for a bud and 5 keys. Checking item history, I believe he sold it for a Orb fire Barnstormer. so a ~1.6 unusual (according to backpack.tf, though its probably lower in value cause it's quite the old price range).

[url]http://www.tf2outpost.com/trade/11577292[/url]: Here it was sold for a N&B Front Runner, or around 20 keys.

[url]http://www.tf2outpost.com/trade/11616103[/url]: Current owner has an offer of a Orb Fire Coppers +10 keys. So ~25 keys total.

In conclusion, the hat often gets 1 bud offers, and is sometimes sold for that, but its relatively easy to get above that in value.