Sale 1:

Sold for Purple Energy Fancy Fedora + Orbiting Fire Deep Cover Operator + ~3 keys in items

http://www.tf2outpost.com/trade/28857352 - B/O of 80

Seller: http://backpack.tf/profiles/76561198053700606#!/compare/1491609600/1491696000

Buyer: http://backpack.tf/profiles/76561197999789029#!/compare/1491609600/1491696000

Easily caps.

X = 80 (Capped by B/O)

Sale 2:

Sold for 70 keys

http://www.tf2outpost.com/trade/28772465 - B/O of 70

Seller: http://backpack.tf/profiles/76561198096389539#!/compare/1487289600/1487376000

Buyer: http://backpack.tf/profiles/76561198165330275#!/compare/1487376000/1487462400

X = 70

Sale 3: (Dupe)

Sold for Disco Beat Down Vintage Merryweather (buyers for 21) + Subatomic Universal Translator (30.5) + Haunted Ghosts Ol’ Snaggletooth (24)

http://www.tf2outpost.com/trade/28739188 - B/O of 70

Seller: http://backpack.tf/profiles/76561198046941961#!/compare/1485648000/1485734400

Buyer: http://backpack.tf/profiles/76561198195141347#!/compare/1485043200/1485734400

X = 70 (Capped by B/O)

Sale 4:

Sold for Green Energy Attendant (Mini at 60 below) + 12 keys

http://www.tf2outpost.com/trade/28784992 - B/O of 66

Seller: http://backpack.tf/profiles/76561198018823628#!/compare/1487289600/1487376000

Buyer: http://backpack.tf/profiles/76561198025644787#!/compare/1487289600/1487376000

X = 66 (Capped by B/O)

Sale 5:

Quicksold for 56 keys

http://www.tf2outpost.com/trade/28870309 - B/O of 66

Seller: http://backpack.tf/profiles/76561198190714350#!/compare/1491782400/1491868800

Buyer: http://backpack.tf/profiles/76561197982127154#!/compare/1491782400/1491868800

X = 56

Sale 6:

Sold to a buyer for 55 keys

Seller: http://backpack.tf/profiles/76561198025644787#!/compare/1490659200/1491004800

Buyer: http://backpack.tf/profiles/76561198053700606#!/compare/1490918400/1491004800

X = 55

Sale 7:

Quicksold for 40 keys

Seller: http://backpack.tf/profiles/76561197999789029#!/compare/1491696000/1491782400

Buyer: http://backpack.tf/profiles/76561198190714350#!/compare/1491696000/1491782400

X = 40

Sale 8:

Bulk for Blizzardy VVF

Seller: http://backpack.tf/profiles/76561198033378852#!/compare/1486512000/1486598400

Buyer: http://backpack.tf/profiles/76561198096389539#!/compare/1486512000/1486598400

Green Energy Attendant:

Sold for Sunbeams Professional’s Panama (57.5) + ~11.5 keys in items

No outpost

Seller: http://backpack.tf/profiles/76561198125791160#!/compare/1491264000/1491350400

Buyer: http://backpack.tf/profiles/76561198038391383#!/compare/1491264000/1491350400

X = 69

2 month old seller at 60:

http://i.imgur.com/hH1nufw.png

http://backpack.tf/u/76561198018823628

Going with 60 on the Attendant.

Sellers:

65 keys:

http://i.imgur.com/C2rdPOe.jpg - 4 days

http://backpack.tf/u/76561197982127154

66 keys:

http://i.imgur.com/lQ7aaAm.png - 20 days

http://backpack.tf/u/76561198080179568

Sales at:

40

55

56

66

70 (2x, 1 dupe)

80

56 and below quicksold/sold to buyers. Excluding 56 and below.

Sale at 80 looks like a bit of an outlier, with sellers for 65 and 66, and majority of the sales in the 66-70 range.

Seller at 65 is 4 days old. Should be fair to round the low-end to 65.

Going with 65-70.