I feel this is a hat that needs a set price, whether my suggestion is accepted or not. Too many hats are just lingering without prices, making trading for/with them quite an ordeal. A lot of the trades are either completed or have been closed due to Inactivity. There are only 2 instances of this particular hat. I recently bought this hat for a Sulphurous Hustler's Hallmark [6 buds] + 2 keys.

Buyers of Phosphorus Black Watch:

http://www.tf2outpost.com/trade/24574447

Sellers of Hallmark (Bp.tf price of 6 buds):

http://www.tf2outpost.com/trade/24583643

http://www.tf2outpost.com/trade/23983538

http://www.tf2outpost.com/trade/24542139 (I paid a Harvest Cowl [~7.5] and received a bud and a half back)

Sellers of Phosphorus Black Watch:

http://www.tf2outpost.com/trade/24312717 (Current Highest offer is a KaW War Pig)

http://www.tf2outpost.com/trade/23886491

http://www.tf2outpost.com/trade/23961874 (Higher-End of Price Suggestion [8 buds])

http://www.tf2outpost.com/trade/24243853 (Looking for 7, Previous Owner payed a DP Viewfinder [~7.5])

Sellers of Dead Presidents Virtual Viewfinder (Outdated Bp.tf price of 8.6 buds):

http://www.tf2outpost.com/trade/24620416 (Low-End only asking 100 keys [~6.66 buds])

http://www.tf2outpost.com/trade/24517381 (Asking 7.5)

http://www.tf2outpost.com/trade/22342335 (High-End looking for 10 buds)