Weird thing.

Sold for 17 Keys

http://backpack.tf/profiles/76561198041822925?time=1449216000 (December 4th)

http://backpack.tf/profiles/76561198041822925?time=1449302400 (December 5th)

Quicksold for 17 Keys

http://backpack.tf/profiles/76561198051032766?time=1449561600 (December 8th)

http://backpack.tf/profiles/76561198051032766?time=1449648000 (December 9th)

Sold for a Blizzardy Storm Glengarry Bonnet(14 Keys with Overpay) and 4 Keys(18 Keys total)(B/O was 15, Outlier)

http://backpack.tf/profiles/76561198047440519?time=1449388800 (December 6th)

http://backpack.tf/profiles/76561198047440519?time=1449475200 (December 7th)

http://www.tf2outpost.com/trade/27474763

Alright this is a tough call. Although it sold really quickly for 17(less than a day), the hat seems to sell commonly for that. Though the 17 Key quicksale indicates that 15 is a low price.

So with all this, we just have to consider the 17 Key quicksell as lucky I suppose :p. 17 Keys should be fine.

Additional Proof/Counter-Proof/Constructive Criticism/Feedback is always appreciated.