Sale 1:

Sold for Purple Energy Outta Sight (75) + Pro. KS Aussie Grenade Launcher (20) + ~28 keys in items

No outpost

Seller: https://backpack.tf/profiles/76561198156255538#!/compare/1497916800/1498003200

Buyer: https://backpack.tf/profiles/76561198174470406#!/compare/1497916800/1498003200

X = 123

Sale 2:

Sold for Chiroptera Venenata Bot Dogger (Suggestion at 85) + Bubbling Bonk Boy (31.5)

http://www.tf2outpost.com/trade/28874354 - B/O of 100

Seller: https://backpack.tf/profiles/76561198055617854#!/compare/1496361600/1496448000

Buyer: https://backpack.tf/profiles/76561198249397292#!/compare/1496361600/1496448000

X = 100 (Capped by B/O)

Sale 3:

Sold with Strange Pro. KS Tomislav (5) for Bubbling VVF (95)

No outpost

Seller: https://backpack.tf/profiles/76561198249397292#!/compare/1496448000/1496534400

Buyer: https://backpack.tf/profiles/76561198156255538#!/compare/1496361600/1496448000

X = 90

Sale 4:

Sold for 65 keys (most likely to a buy order)

Seller: https://backpack.tf/profiles/76561198151650301#!/compare/1499126400/1499385600

Buyer: https://backpack.tf/profiles/76561198056793444#!/compare/1499299200/1499385600

X = 65

Sale 5:

Sold for Bubbling Virtual Viewfinder (95)

No outpost

Seller: https://backpack.tf/profiles/76561198015070727#!/compare/1498867200/1498953600

Buyer: https://backpack.tf/profiles/76561198156315732#!/compare/1498867200/1498953600

Probably best not to take a second sale that was used on the VVF. This will end up in the range here anyways, though.

Sale 6:

Sold with Infernal Smoke Conga for Searing Plasma Hong Kong Cone + Smoking Bombing Run + <1 key in items

Seller: https://backpack.tf/profiles/76561198174470406#!/compare/1500336000/1500422400

Buyer: https://backpack.tf/profiles/76561198216561389#!/compare/1500422400/1500508800

Would be better off being used on the HKC

Sale 7:

Sold for Haunted Ghosts Chill Chullo

No outpost

Seller: https://backpack.tf/profiles/76561198156315732#!/compare/1500768000/1500854400

Buyer: https://backpack.tf/profiles/76561198029895408#!/compare/1500854400/1500940800

Better to use on the Chullo, due to lack of B/O here.

Sale 8:

Sold with Scorching Prancer's Pride for Burning Blast Defense

No outpost

Seller: https://backpack.tf/profiles/76561198029895408#!/compare/1501459200/1501545600

Buyer: https://backpack.tf/profiles/76561198120467518#!/compare/1501200000/1501545600

Seems pretty low, excluding this sale.

Sellers:

100 keys:

http://i.imgur.com/WVRrcAD.png - 1 month

103 keys:

http://i.imgur.com/CovuFSz.png - 3 days, probably lowered/re-listed

Sales at:

65

90

100

123

123 looks like an outlier, and current sellers show that it is pretty high. B/O was most likely lower, too. Excluding 123.

65 most likely went to a buy order, and is a large outlier. Excluding 65.

Going with 90-100.