Currently more expensive than some Flames unusuals.

http://backpack.tf/item/5227061399

Sale 1) Sold for 17 Keys + ~3 Keys of Items

http://backpack.tf/profiles/76561198108148076#!/compare/1486684800/1486771200

17 + 3 = 20 Keys

Sale 2) Sold for 20 Keys

http://backpack.tf/profiles/76561198275582056#!/compare/1486857600/1487030400

Sale 3) Sold for a Tesla Coil Big Topper

http://backpack.tf/profiles/76561198036221461#!/compare/1487030400/1487203200

http://www.tf2outpost.com/trade/28780273 - Capped by the Buyout of 21 Keys

http://backpack.tf/item/5192925407

Sale 4) Sold + 3 Keys + Carlton (~1 Key) for a Stormy Storm Anger

http://backpack.tf/profiles/76561198172968714#!/compare/1486684800/1486771200 - Buyer's Backpack

http://www.tf2outpost.com/trade/28744286 - Capped by the Buyout of 25 Keys

Sale 5) Sold for a Miami Nights Big Elfin Deal (16.5 Keys)

http://backpack.tf/profiles/76561198172968714#!/compare/1486944000/1487116800

Low Outlier, but supports a drop.

Elfin Mini

http://backpack.tf/profiles/76561198014501079#!/compare/1491177600/1491264000 - Sold for 14 Keys

http://www.tf2outpost.com/trade/28851440 - Not a quicksell.

http://backpack.tf/profiles/76561198117542709#!/compare/1491177600/1491264000 - Quicksold for 14 Keys + 6 Refined

http://backpack.tf/profiles/76561198107520045#!/compare/1490313600/1490400000 - Sold for 17 Keys

http://backpack.tf/profiles/76561198065510619#!/compare/1488240000/1488412800 - Sold for 16 Keys

http://backpack.tf/profiles/76561198172968714#!/compare/1487203200/1487289600 - Sold for 16 Keys

Taking 16.5 Keys

Sale 6) Sold + ~8 Keys of Items for a Haunted Ghosts Safe'n'Sound (30 Keys)

http://backpack.tf/profiles/76561198123241477#!/compare/1487203200/1487376000

30 - 8 = 22 Keys

Safe'n'Sound Mini

http://imgur.com/a/q5ZmO - Taking 30 Keys

Sale 7) Sold + ~2 Keys of Items for a Scorching Flames Hard Counter

http://backpack.tf/profiles/76561198066195760#!/compare/1487289600/1487376000

Fits in the range, supports the high end.