Resubmitting since the guy hasn't closed his suggestion. This thing does actually sell for a high price, but not as low as what the other person put it at. From looking at Outpost, there's less than a page, but this is what I found.

CLASSIFIEDS:

http://backpack.tf/classifieds/search/30075/6/0 - One seller at 2.5 keys, but already sold, and 2 more sellers at 3 and 4 keys.

PEOPLE SELLING/SOLD FOR OVER 3 KEYS:

http://www.tf2outpost.com/trade/11718696 - Selling at 5 keys. No buyers and people offering ~2 keys.

http://www.tf2outpost.com/trade/11846131 - Selling at 4 keys. No offers/buyers yet.

http://www.tf2outpost.com/trade/11832080 - Person is buying for 3.5 keys? Not confirmed yet since it looks like he's buying but no trade has gone through yet since the item history shows it's still with the owner.

http://www.tf2outpost.com/trade/11850208 - Selling for 3 keys + a craft hat. Bumped 6 hrs ago and is 9 hrs old.

http://www.tf2outpost.com/trade/11717203 - Sold it for 11 ref + an Anger + a Pip-Boy + a G. Foppish + an Area 451, altogether selling for ~3.1 keys.

http://www.tf2outpost.com/trade/11789868 - Has a B/O of 5 keys. People have offered around ~2-2.8 keys

http://www.tf2outpost.com/trade/11839885 - Selling for 3.5 keys or offers. Bumped 13 hrs ago and is 20 hrs old.

THAT SECTION:

http://www.tf2outpost.com/trade/11794384 - Offered a White Dashin Hashashin (~3.6 keys) but no longer has it.

PEOPLE SELLING/SOLD AT 3 KEYS:

http://www.tf2outpost.com/trade/11855555 - Sold around 5 hrs ago.

http://www.tf2outpost.com/trade/11851822 - Selling it at 3 keys, bumped 3 hrs ago and is 8 hrs old.

http://www.tf2outpost.com/trade/11850301 - Bumped 5 hrs ago and is 9 hrs old.

http://www.tf2outpost.com/trade/11838171 - Selling at 3 keys. 22 hrs old, and last bumped 9 hrs ago.

http://www.tf2outpost.com/trade/11837911 - Selling at 3 keys. Bumped and made 22 hrs ago.

http://www.tf2outpost.com/trade/11742110 - Has sold one at 3 keys.

PEOPLE GETTING OFFERED 3 KEYS OR MORE:

http://www.tf2outpost.com/trade/11832945 - Person offered 3 keys 20 hrs ago.

http://www.tf2outpost.com/trade/11758355 - Person offered 3 keys + a craft hat for the Mair Mask.

Conclusion: Many people selling for around 3 to 3+ keys, and the 3 key sellers seem to have a bit of an easier time but it's not considered a quicksell. Please feel free to provide counterproof if you find any. Thanks for your consideration.